Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 36
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
2.
Eur J Clin Pharmacol ; 79(12): 1613-1621, 2023 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-37737911

RESUMO

PURPOSE: The primary aim of this study was to investigate the effect of including the Dutch National Pharmacotherapy Assessment (DNPA) in the medical curriculum on the level and development of prescribing knowledge and skills of junior doctors. The secondary aim was to evaluate the relationship between the curriculum type and the prescribing competence of junior doctors. METHODS: We re-analysed the data of a longitudinal study conducted in 2016 involving recently graduated junior doctors from 11 medical schools across the Netherlands and Belgium. Participants completed three assessments during the first year after graduation (around graduation (+ / - 4 weeks), and 6 months, and 1 year after graduation), each of which contained 35 multiple choice questions (MCQs) assessing knowledge and three clinical case scenarios assessing skills. Only one medical school used the DNPA in its medical curriculum; the other medical schools used conventional means to assess prescribing knowledge and skills. Five medical schools were classified as providing solely theoretical clinical pharmacology and therapeutics (CPT) education; the others provided both theoretical and practical CPT education (mixed curriculum). RESULTS: Of the 1584 invited junior doctors, 556 (35.1%) participated, 326 (58.6%) completed the MCQs and 325 (58.5%) the clinical case scenarios in all three assessments. Junior doctors whose medical curriculum included the DNPA had higher knowledge scores than other junior doctors (76.7% [SD 12.5] vs. 67.8% [SD 12.6], 81.8% [SD 11.1] vs. 76.1% [SD 11.1], 77.0% [12.1] vs. 70.6% [SD 14.0], p < 0.05 for all three assessments, respectively). There was no difference in skills scores at the moment of graduation (p = 0.110), but after 6 and 12 months junior doctors whose medical curriculum included the DNPA had higher skills scores (both p < 0.001). Junior doctors educated with a mixed curriculum had significantly higher scores for both knowledge and skills than did junior doctors educated with a theoretical curriculum (p < 0.05 in all assessments). CONCLUSION: Our findings suggest that the inclusion of the knowledge focused DNPA in the medical curriculum improves the prescribing knowledge, but not the skills, of junior doctors at the moment of graduation. However, after 6 and 12 months, both the knowledge and skills were higher in the junior doctors whose medical curriculum included the DNPA. A curriculum that provides both theoretical and practical education seems to improve both prescribing knowledge and skills relative to a solely theoretical curriculum.


Assuntos
Currículo , Educação Médica , Humanos , Estudos Longitudinais , Países Baixos , Corpo Clínico Hospitalar/educação , Competência Clínica
3.
Br J Clin Pharmacol ; 89(4): 1431-1451, 2023 04.
Artigo em Inglês | MEDLINE | ID: mdl-36403122

RESUMO

AIMS: Prescribing errors among junior doctors are common in clinical practice because many lack prescribing competence after graduation. This is in part due to inadequate education in clinical pharmacology and therapeutics (CP&T) in the undergraduate medical curriculum. To support CP&T education, it is important to determine which drugs medical undergraduates should be able to prescribe safely and effectively without direct supervision by the time they graduate. Currently, there is no such list with broad-based consensus. Therefore, the aim was to reach consensus on a list of essential drugs for undergraduate medical education in the Netherlands. METHODS: A two-round modified Delphi study was conducted among pharmacists, medical specialists, junior doctors and pharmacotherapy teachers from all eight Dutch academic hospitals. Participants were asked to indicate whether it was essential that medical graduates could prescribe specific drugs included on a preliminary list. Drugs for which ≥80% of all respondents agreed or strongly agreed were included in the final list. RESULTS: In all, 42 (65%) participants completed the two Delphi rounds. A total of 132 drugs (39%) from the preliminary list and two (3%) newly proposed drugs were included. CONCLUSIONS: This is the first Delphi consensus study to identify the drugs that Dutch junior doctors should be able to prescribe safely and effectively without direct supervision. This list can be used to harmonize and support the teaching and assessment of CP&T. Moreover, this study shows that a Delphi method is suitable to reach consensus on such a list, and could be used for a European list.


Assuntos
Medicamentos Essenciais , Educação de Graduação em Medicina , Humanos , Educação de Graduação em Medicina/métodos , Técnica Delphi , Competência Clínica , Currículo
4.
Clin Pharmacol Ther ; 113(3): 600-606, 2023 03.
Artigo em Inglês | MEDLINE | ID: mdl-36325997

RESUMO

The relationship between race and biology is complex. In contemporary medical science, race is a social construct that is measured via self-identification of study participants. But even though race has no biological essence, it is often used as variable in medical guidelines (e.g., treatment recommendations specific for Black people with hypertension). Such recommendations are based on clinical trials in which there was a significant correlation between self-identified race and actual, but often unmeasured, health-related factors such as (pharmaco)genetics, diet, sun exposure, etc. Many teachers are insufficiently aware of this complexity. In their classes, they (unintentionally) portray self-reported race as having a biological essence. This may cause students to see people of shared race as biologically or genetically homogeneous, and believe that race-based recommendations are true for all individuals (rather than reflecting the average of a heterogeneous group). This medicalizes race and reinforces already existing healthcare disparities. Moreover, students may fail to learn that the relation between race and health is easily biased by factors such as socioeconomic status, racism, ancestry, and environment and that this limits the generalizability of race-based recommendations. We observed that the clinical case vignettes that we use in our teaching contain many stereotypes and biases, and do not generally reflect the diversity of actual patients. This guide, written by clinical pharmacology and therapeutics teachers, aims to help our colleagues and teachers in other health professions to reflect on and improve our teaching on race-based medical guidelines and to make our clinical case vignettes more inclusive and diverse.


Assuntos
Farmacologia Clínica , Racismo , Humanos , Estudantes , Classe Social , Aprendizagem
5.
NPJ Sci Learn ; 7(1): 23, 2022 Sep 30.
Artigo em Inglês | MEDLINE | ID: mdl-36180446

RESUMO

The European Open Platform for Prescribing Education (EurOP2E) seeks to improve and harmonize European clinical pharmacology and therapeutics (CPT) education by facilitating international collaboration and sharing problem-based, online, open educational resources. The COVID-19 pandemic forced teachers to switch to virtual modalities, highlighting the need for high-quality online teaching materials. The goal of this study was to establish the online problem-based teaching resources needed to sustain prescribing education during the pandemic and thereafter. A nominal group technique study was conducted with prescribing teachers from 15 European countries. Results were analyzed through thematic analysis. In four meetings, 20 teachers from 15 countries proposed and ranked 35 teaching materials. According to the participants, the most necessary problem-based-online teaching materials related to three overarching themes. Related to learning outcomes for CPT, participants proposed creating prescription scenarios, including materials focusing on background knowledge and resources on personalized medicine and topical/ethical issues such as the prescription's impact on planetary health. Second, related to teaching, they proposed online case discussions, gamification and decision support systems. Finally, in relation to faculty development, they recommend teacher courses, a repository of reusable exam questions and harmonized formularies. Future work will aim to collaboratively produce such materials.

6.
Eur J Clin Pharmacol ; 78(11): 1861-1862, 2022 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-36180797

RESUMO

PURPOSE: In the wake of the coronavirus disease 2019 (COVID-19) pandemic, support in clinical trials by students of human medicine and related disciplines has become of even greater importance than in pre-pandemic times. Documentation in clinical trials adheres to the principles of Good Clinical Practice (GCP), and healthcare professionals involved in the conduct of clinical trials-including students-are obliged to perform documentation in accordance with GCP principles. Unprecedented challenges have arisen with regard to the appropriate training of students as training courses in presence had largely to be suspended due to social-distancing regulations during the heyday of the COVID-19 pandemic. Therefore, novel training formats and self-study training materials for students working in clinical trials are urgently warranted. METHODS: To overcome this shortcoming and to define a common quality standard, an interdisciplinary, multiprofessional (physicians, study nurses, medical students), and binational (Germany, The Netherlands) expert panel convened and devised the Students' guide to documentation in clinical trials. RESULTS: Following a brief description of the different roles in clinical trials (e.g., sponsor, (principal) investigator, monitor) and an introduction into the principles of GCP, the documentation of adverse events, concomitant medication, medical history, and quality control are comprehensively discussed. The Guide concludes with a trilingual medical dictionary (English, German, Dutch) and with recommendations of pertinent literature for further reading. CONCLUSION: Serving both as textbook for self-training and as (quick-) reference work for the daily routine, the Guide has specifically been designed to complement, but not to replace practical training courses for students. While primarily addressed at students of human medicine and related disciplines, the Guide can also be of high relevance and utility to other healthcare professionals involved in the conduct of clinical trials.


Assuntos
COVID-19 , Estudantes de Medicina , Ensaios Clínicos como Assunto , Documentação , Alemanha , Humanos , Pandemias
7.
Br J Clin Pharmacol ; 88(12): 5218-5226, 2022 12.
Artigo em Inglês | MEDLINE | ID: mdl-35716366

RESUMO

AIM: The aim of this study was to investigate how the prescribing knowledge and skills of junior doctors in the Netherlands and Belgium develop in the year after graduation. We also analysed differences in knowledge and skills between surgical and nonsurgical junior doctors. METHODS: This international, multicentre (n = 11), longitudinal study analysed the learning curves of junior doctors working in various specialties via three validated assessments at about the time of graduation, and 6 months and 1 year after graduation. Each assessment contained 35 multiple choice questions (MCQs) on medication safety (passing grade ≥85%) and three clinical scenarios. RESULTS: In total, 556 junior doctors participated, 326 (58.6%) of whom completed the MCQs and 325 (58.5%) the clinical case scenarios of all three assessments. Mean prescribing knowledge was stable in the year after graduation, with 69% (SD 13) correctly answering questions at assessment 1 and 71% (SD 14) at assessment 3, whereas prescribing skills decreased: 63% of treatment plans were considered adequate at assessment 1 but only 40% at assessment 3 (P < .001). While nonsurgical doctors had similar learning curves for knowledge and skills as surgical doctors (P = .53 and P = .56 respectively), their overall level was higher at all three assessments (all P < .05). CONCLUSION: These results show that junior doctors' prescribing knowledge and skills did not improve while they were working in clinical practice. Moreover, their level was under the predefined passing grade. As this might adversely affect patient safety, educational interventions should be introduced to improve the prescribing competence of junior doctors.


Assuntos
Competência Clínica , Corpo Clínico Hospitalar , Padrões de Prática Médica , Humanos , Competência Clínica/estatística & dados numéricos , Seguimentos , Estudos Longitudinais
10.
Clin Chim Acta ; 510: 707-710, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32946792

RESUMO

The existence of glucosylated cholesterol (GlcChol) in tissue has recently been recognized. GlcChol is generated from glucosylceramide (GlcCer) and cholesterol through transglucosylation by two retaining ß-glucosidases, GBA and GBA2. Given the abundance of GBA, GlcCer and cholesterol in the skin's stratum corneum (SC), we studied the occurrence of GlcChol. A significant amount of GlcChol was detected in SC (6 pmol/mg weight). The ratio GlcChol/GlcCer is higher in SC than epidermis, 0.083 and 0.011, respectively. Examination of GlcChol in patients with Netherton syndrome revealed comparable levels (11 pmol/mg). Concluding, GlcChol was identified as a novel component in SC and is likely locally metabolized by GBA. The physiological function of GlcChol in the SC warrants future investigation.


Assuntos
Glucosilceramidase , Glucosilceramidas , Colesterol , Humanos , Pele
11.
J Lipid Res ; 61(6): 859-869, 2020 06.
Artigo em Inglês | MEDLINE | ID: mdl-32265319

RESUMO

Individuals with Netherton syndrome (NTS) have increased serine protease activity, which strongly impacts the barrier function of the skin epidermis and leads to skin inflammation. Here, we investigated how serine protease activity in NTS correlates with changes in the stratum corneum (SC) ceramides, which are crucial components of the skin barrier. We examined two key enzymes involved in epidermal ceramide biosynthesis, ß-glucocerebrosidase (GBA) and acid-sphingomyelinase (ASM). We compared in situ expression levels and activities of GBA and ASM between NTS patients and controls and correlated the expression and activities with i) SC ceramide profiles, ii) in situ serine protease activity, and iii) clinical presentation of patients. Using activity-based probe labeling, we visualized and localized active epidermal GBA, and a newly developed in situ zymography method enabled us to visualize and localize active ASM. Reduction in active GBA in NTS patients coincided with increased ASM activity, particularly in areas with increased serine protease activity. NTS patients with scaly erythroderma exhibited more pronounced anomalies in GBA and ASM activities than patients with ichthyosis linearis circumflexa. They also displayed a stronger increase in SC ceramides processed via ASM. We conclude that changes in the localization of active GBA and ASM correlate with i) altered SC ceramide composition in NTS patients, ii) local serine protease activity, and iii) the clinical manifestation of NTS.


Assuntos
Ceramidas/metabolismo , Metabolismo dos Lipídeos , Síndrome de Netherton/metabolismo , Peptídeo Hidrolases/metabolismo , Pele/enzimologia , Humanos , Síndrome de Netherton/enzimologia , Pele/metabolismo
12.
J Clin Med ; 9(3)2020 Mar 09.
Artigo em Inglês | MEDLINE | ID: mdl-32182893

RESUMO

Glucocerebrosidase (GCase) is a retaining ß-glucosidase with acid pH optimum metabolizing the glycosphingolipid glucosylceramide (GlcCer) to ceramide and glucose. Inherited deficiency of GCase causes the lysosomal storage disorder named Gaucher disease (GD). In GCase-deficient GD patients the accumulation of GlcCer in lysosomes of tissue macrophages is prominent. Based on the above, the key function of GCase as lysosomal hydrolase is well recognized, however it has become apparent that GCase fulfills in the human body at least one other key function beyond lysosomes. Crucially, GCase generates ceramides from GlcCer molecules in the outer part of the skin, a process essential for optimal skin barrier property and survival. This review covers the functions of GCase in and beyond lysosomes and also pays attention to the increasing insight in hitherto unexpected catalytic versatility of the enzyme.

13.
Artigo em Inglês | MEDLINE | ID: mdl-32092464

RESUMO

Patients with Atopic Dermatitis (AD) suffer from inflamed skin and skin barrier defects. Proper formation of the outermost part of the skin, the stratum corneum (SC), is crucial for the skin barrier function. In this study we analyzed the localization and activity of lipid enzymes ß-glucocerebrosidase (GBA) and acid sphingomyelinase (ASM) in the skin of AD patients and controls. Localization of both the expression and activity of GBA and ASM in the epidermis of AD patients was altered, particularly at lesional skin sites. These changes aligned with the altered SC lipid composition. More specifically, abnormal localization of GBA and ASM related to an increase in specific ceramide subclasses [AS] and [NS]. Moreover we related the localization of the enzymes to the amounts of SC ceramide subclasses and free fatty acids (FFAs). We report a correlation between altered localization of active GBA and ASM and a disturbed SC lipid composition. Localization of antimicrobial peptide beta-defensin-3 (HBD-3) and AD biomarker Thymus and Activation Regulated Chemokine (TARC) also appeared to be diverging in AD skin compared to control. This research highlights the relation between correct localization of expressed and active lipid enzymes and a normal SC lipid composition for a proper skin barrier.


Assuntos
Dermatite Atópica/imunologia , Epiderme/patologia , Glucosilceramidase/metabolismo , Metabolismo dos Lipídeos/imunologia , Esfingomielina Fosfodiesterase/metabolismo , Adolescente , Adulto , Biópsia , Estudos de Casos e Controles , Ceramidas/análise , Ceramidas/metabolismo , Quimiocina CCL17/metabolismo , Dermatite Atópica/patologia , Epiderme/química , Epiderme/enzimologia , Ácidos Graxos não Esterificados/análise , Ácidos Graxos não Esterificados/metabolismo , Feminino , Voluntários Saudáveis , Humanos , Masculino , Perda Insensível de Água/imunologia , Adulto Jovem , beta-Defensinas/metabolismo
15.
Biochim Biophys Acta Mol Cell Biol Lipids ; 1864(9): 1206-1213, 2019 09.
Artigo em Inglês | MEDLINE | ID: mdl-31112754

RESUMO

The cornified lipid envelope (CLE) is a lipid monolayer covalently bound to the outside of corneocytes and is part of the stratum corneum (SC). The CLE is suggested to act as a scaffold for the unbound SC lipids. By profiling the bound CLE ceramides, a new subclass was discovered and identified as an omega-hydroxylated dihydrosphingosine (OdS) ceramide. Bound glucosylceramides were observed in superficial SC layers of healthy human skin. To investigate the relation between bound and unbound SC ceramides, the composition of both fractions was analyzed and compared. Selectivity in ceramide binding towards unsaturated ceramides and ceramides with a shorter chain length was observed. The selectivity in ceramide species bound to the cornified envelope is thought to have a physiological function in corneocyte flexibility. Next, it was examined if skin models exhibit an altered bound ceramide composition and if the composition was dependent on liver X-receptor (LXR) activation. The effects of an LXR agonist and antagonist on the bound ceramides composition of a full thickness model (FTM) were analyzed. In FTMs, a decreased amount of bound ceramides was observed compared to native human skin. Furthermore, FTMs had a bound ceramide fraction which consisted mostly of unsaturated and shorter ceramides. The LXR antagonist had a normalizing effect on the FTM bound ceramide composition. The agonist exhibited minimal effects. We show that ceramide binding is a selective process, yet, still is contingent on lipid synthesized.


Assuntos
Ceramidas/metabolismo , Receptores X do Fígado/antagonistas & inibidores , Pele/metabolismo , Sítios de Ligação/efeitos dos fármacos , Ceramidas/química , Humanos , Hidroxilação , Receptores X do Fígado/agonistas , Receptores X do Fígado/metabolismo , Pele/efeitos dos fármacos , Esfingosina/análogos & derivados , Esfingosina/química , Esfingosina/metabolismo
16.
J Lipid Res ; 59(2): 250-260, 2018 02.
Artigo em Inglês | MEDLINE | ID: mdl-29217624

RESUMO

Restoring the lipid homeostasis of the stratum corneum (SC) is a common strategy to enhance skin barrier function. Here, we used a ceramide containing vernix caseosa (VC)-based formulation and were able to accelerate barrier recovery in healthy volunteers. The recovery was examined over 16 days by monitoring trans-epidermal water loss (TEWL) after barrier disruption by tape-stripping. Four skin sites were used to examine the effects of both treatment and barrier recovery. After 16 days, samples were harvested at these sites to examine the SC ceramide composition and lipid organization. Changes in ceramide profiles were identified using principal component analysis. After barrier recovery, the untreated sites showed increased levels of ceramide subclass AS and ceramides with a 34 total carbon-atom chain length, while the mean ceramide chain length was reduced. These changes were diminished by treatment with the studied formulation, which concurrently increased the formulated ceramides. Correlations were observed between SC lipid composition, lipid organization, and TEWL, and changes in the ceramide subclass composition suggest changes in the ceramide biosynthesis. These results suggest that VC-based formulations enhance skin barrier recovery and are attractive candidates to treat skin disorders with impaired barrier properties.


Assuntos
Lipídeos/biossíntese , Pele/metabolismo , Verniz Caseoso/metabolismo , Adolescente , Adulto , Feminino , Humanos , Masculino , Verniz Caseoso/química , Adulto Jovem
17.
J Lipid Res ; 58(12): 2299-2309, 2017 12.
Artigo em Inglês | MEDLINE | ID: mdl-29025868

RESUMO

Epidermal ß-glucocerebrosidase (GBA1), an acid ß-glucosidase normally located in lysosomes, converts (glucosyl)ceramides into ceramides, which is crucial to generate an optimal barrier function of the outermost skin layer, the stratum corneum (SC). Here we report on two developed in situ methods to localize active GBA in human epidermis: i) an optimized zymography method that is less labor intensive and visualizes enzymatic activity with higher resolution than currently reported methods using either substrate 4-methylumbelliferyl-ß-D-glucopyranoside or resorufin-ß-D-glucopyranoside; and ii) a novel technique to visualize active GBA1 molecules by their specific labeling with a fluorescent activity-based probe (ABP), MDW941. The latter method pro-ved to be more robust and sensitive, provided higher resolution microscopic images, and was less prone to sample preparation effects. Moreover, in contrast to the zymography substrates that react with various ß-glucosidases, MDW941 specifically labeled GBA1. We demonstrate that active GBA1 in the epidermis is primarily located in the extracellular lipid matrix at the interface of the viable epidermis and the lower layers of the SC. With ABP-labeling, we observed reduced GBA1 activity in 3D-cultured skin models when supplemented with the reversible inhibitor, isofagomine, irrespective of GBA expression. This inhibition affected the SC ceramide composition: MS analysis revealed an inhibitor-dependent increase in the glucosylceramide:ceramide ratio.


Assuntos
Ensaios Enzimáticos , Corantes Fluorescentes/química , Glucosilceramidase/análise , Pele/enzimologia , Coloração e Rotulagem/métodos , Benzoxazinas/química , Compostos de Boro/química , Cicloexanóis/química , Compostos de Epóxi/química , Expressão Gênica , Glucosídeos/química , Glucosilceramidase/metabolismo , Humanos , Himecromona/análogos & derivados , Himecromona/química , Técnicas de Cultura de Tecidos
18.
J Dermatol Sci ; 88(1): 57-66, 2017 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-28571749

RESUMO

BACKGROUND: The barrier dysfunction in atopic dermatitis (AD) skin correlates with stratum corneum (SC) lipid abnormalities including reduction of global lipid content, shorter ceramide (CER) as well as free fatty acid (FFA) chain length and altered CER subclass levels. However, the underlying cause of these changes in lipid composition has not been fully investigated. AIM: We investigated whether the expression of CER and FFA biosynthesis enzymes are altered in AD skin compared with control skin and determine whether changes in enzyme expression can be related with changes in lipid composition. METHODS: In AD patients and controls the expression of enzymes involved in the biosynthesis of FFAs and CERs was analyzed in relation to the SC lipid composition. These enzymes include stearoyl CoA desaturase (SCD), elongase 1 (ELOVL1) and ELOVL6 involved in FFA synthesis and ß-glucocerebrosidase (GBA), acid-sphingomyelinase (aSmase), ceramide synthase 3 (CerS3) involved in CER synthesis. In TH2 treated human skin equivalents (AD HSEs) mimicking lesional AD skin, the mRNA expression of these enzymes was investigated. RESULTS: The results reveal an altered expression of SCD and ELOVL1 in AD lesional skin. This was accompanied by functional changes displayed by increased unsaturated FFAs (SCD) and reduced FFA C22-C28 (ELOVL1) in AD lesional skin. The expression of GBA, aSmase and CerS3 were also altered in lesional skin. The CER composition in AD lesional skin showed corresponding changes such as increased CER AS and NS (aSmase) and decreased esterified ω-hydroxy CERs (CerS3). In support of the results from AD skin, the AD HSEs showed reduced mRNA ELOVL1, GBA and a Smase levels. CONCLUSION: This study shows that alterations in the expression of key enzymes involved in SC lipid synthesis contribute to changes in the lipid composition in AD skin and inflammation may influence expression of these enzymes.


Assuntos
Ceramidas/metabolismo , Dermatite Atópica/patologia , Epiderme/metabolismo , Ácidos Graxos não Esterificados/metabolismo , Lipogênese , Acetiltransferases/metabolismo , Adulto , Células Cultivadas , Ceramidas/análise , Ceramidas/biossíntese , Citocinas/imunologia , Dermatite Atópica/imunologia , Células Epidérmicas , Epiderme/patologia , Elongases de Ácidos Graxos , Ácidos Graxos não Esterificados/análise , Ácidos Graxos não Esterificados/biossíntese , Feminino , Glucosilceramidase/metabolismo , Humanos , Queratinócitos , Masculino , Esfingomielina Fosfodiesterase/metabolismo , Esfingosina N-Aciltransferase/metabolismo , Estearoil-CoA Dessaturase/metabolismo , Células Th2/metabolismo , Adulto Jovem
19.
PLoS One ; 12(3): e0174478, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28333992

RESUMO

Full thickness human skin models (FTMs) contain an epidermal and a dermal equivalent. The latter is composed of a collagen dermal matrix which harbours fibroblasts. Current epidermal barrier properties of FTMs do not fully resemble that of native human skin (NHS), which makes these human skin models less suitable for barrier related studies. To further enhance the resemblance of NHS for epidermal morphogenesis and barrier formation, we modulated the collagen dermal matrix with the biocompatible polymer chitosan. Herein, we report that these collagen-chitosan FTMs (CC-FTMs) possess a well-organized epidermis and maintain both the early and late differentiation programs as in FTMs. Distinctively, the epidermal cell activation is reduced in CC-FTMs to levels observed in NHS. Dermal-epidermal interactions are functional in both FTM types, based on the formation of the basement membrane. Evaluation of the barrier structure by the organization of the extracellular lipid matrix of the stratum corneum revealed an elongated repeat distance of the long periodicity phase. The ceramide composition exhibited a higher resemblance of the NHS, based on the carbon chain-length distribution and subclass profile. The inside-out barrier functionality indicated by the transepidermal water loss is significantly improved in the CC-FTMs. The expression of epidermal barrier lipid processing enzymes is marginally affected, although more restricted to a single granular layer. The novel CC-FTM resembles the NHS more closely, which makes them a promising tool for epidermal barrier related studies.


Assuntos
Quitosana/metabolismo , Colágeno/metabolismo , Epiderme/metabolismo , Pele Artificial , Membrana Basal/citologia , Membrana Basal/metabolismo , Diferenciação Celular , Células Epidérmicas , Humanos , Queratinócitos/metabolismo
20.
Exp Dermatol ; 26(1): 36-43, 2017 01.
Artigo em Inglês | MEDLINE | ID: mdl-27305861

RESUMO

In several skin diseases, both the lipid composition and organization in the stratum corneum (SC) are altered which contributes to the impaired skin barrier function in patients. One of the approaches for skin barrier repair is treatment with topical formulations to normalize SC lipid composition and organization. Vernix caseosa (VC), a white cheesy cream on the skin during gestational delivery, has shown to enhance skin barrier repair. In this study, we examined how a fatty acid (FA) containing formulation mimicking the lipid composition of VC interacts with the lipid matrix in the SC. The formulation was applied on ex vivo human skin after SC removal. Subsequently, the ex vivo human skin generated SC during culture. The effect of FA containing formulations on the lipid organization and composition in the regenerated SC was analysed by Fourier transform infrared (FTIR) spectroscopy and liquid chromatography mass spectroscopy (LC/MS), respectively. FTIR results demonstrate that the FAs are intercalated in the lipid matrix of the regenerated SC and partition in the same lattice with the endogenous SC lipids, thereby enhancing the fraction of lipids forming an orthorhombic (very dense) packing in the SC. LC/MS data show that the topically applied FAs are elongated before intercalation in the lipid matrix and are thus involved in the lipid biosynthesis in the skin.


Assuntos
Epiderme/metabolismo , Ácidos Graxos/administração & dosagem , Ácidos Graxos/metabolismo , Metabolismo dos Lipídeos , Fenômenos Fisiológicos da Pele , Administração Cutânea , Cromatografia Líquida , Epiderme/química , Ácidos Graxos/química , Humanos , Espectrometria de Massas , Espectroscopia de Infravermelho com Transformada de Fourier , Técnicas de Cultura de Tecidos , Verniz Caseoso/química
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...