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1.
BMC Health Serv Res ; 24(1): 150, 2024 Jan 30.
Artigo em Inglês | MEDLINE | ID: mdl-38291443

RESUMO

OBJECTIVES: Since 2018, four establishments in Quebec have been instrumental in implementing the PAROLE-Onco program, which introduced accompanying patients (APs) into healthcare teams to improve cancer patients' experience. APs are patient advisors who have acquired specific experiential knowledge related to living with cancer, using services, and interacting with healthcare professionals. They are therefore in a unique and reliable position to be able to provide emotional, informational, cognitive and navigational support to patients who are dealing with cancer. We aimed to explore APs' perspectives regarding the limiting and facilitating factors in terms of how they are integrated into the clinical oncology teams. METHODS: A qualitative study based on semi-structured interviews and focus groups was conducted with 20 APs at the beginning of their intervention (T1) and, two years later, during a second data collection (T2). Limiting and facilitating factors of APs' integration into clinical teams were analyzed in terms of governance, culture, resources and tools. RESULTS: The limited factors raised by APs to be integrated into clinical teams include the following: confusion about the specific roles played by APs, lifting the egos of certain professionals who feel they are already doing what APs typically do, lack of identification of patient needs, absence of APs in project governance organizational boundaries, and team members' availability. Various communication challenges were also raised, resulting in the program being inadequately promoted among patients. Also mentioned as limiting factors were the lack of time, space and compensation. Creating opportunities for team members to meet with APs, building trust and teaching team members how APs' activities complement theirs were enhancing factors. Other facilitators include APs being involved in decision-making committees, being leaders in promoting the PAROLE-Onco program to patients and clinical team members and creating opportunities to communicate with team members to help enhance their work and provide feedback to improve patient services. Awareness of APs' added value for the team and patients is also a key facilitator. Regarding tools, offering accompanying services by telephone allows both patients and APs to benefit from the flexibility they need. CONCLUSION: Over time, APs were able to identify optimal factors for successful implementation. Recommendations include APs and professionals working in co-construction on organization, leadership, resources and status factors. This could help catalyze a change in culture within health establishments and allow people dealing with cancer to benefit from the experiential knowledge of other patients within their clinical team.


Assuntos
Pessoal de Saúde , Neoplasias , Humanos , Grupos Focais , Pesquisa Qualitativa , Oncologia , Neoplasias/terapia
2.
BMC Cancer ; 23(1): 369, 2023 Apr 22.
Artigo em Inglês | MEDLINE | ID: mdl-37087438

RESUMO

BACKGROUND: Centre hospitalier de l'Université de Montréal in Canada introduced accompanying patients (APs) into the breast cancer care trajectory. APs are patients who have been treated for breast cancer and have been integrated into the clinical team to expand the services offered to people affected by cancer. This study describes the profiles of the people who received the support and explores whether one-offs vs ongoing encounters with APs influence their experience of care, on self-efficacy in coping with cancer, and on their level of psychological distress. METHODS: An exploratory cross-sectional study was carried out among patients to compare patients who had one encounter with an AP (G1) with those who had had several encounters (G2). Five questionnaires were administered on socio-demographic characteristics, care pathway, evaluation of the support experience, self-efficacy in coping with cancer, and level of psychological distress. Logbooks, completed by the APs, determined the number of encounters. Linear regression models were used to evaluate the associations between the number of encounters, patient characteristics, care pathway, number of topics discussed, self-efficacy measures in coping with cancer, and level of psychological distress. RESULTS: Between April 2020 and December 2021, 60% of 535 patients who were offered support from an AP accepted. Of these, one hundred and twenty-four patients participated in the study. The study aimed to recruit a minimum of 70 patients with the expectation of obtaining at least 50 participants, assuming a response rate of 70%. There were no differences between G1 and G2 in terms of sociodemographic data and care pathways. Statistical differences were found between G1 and G2 for impacts on and the return to daily life (p = 0.000), the return to the work and impacts on professional life (p = 0.044), announcement of a diagnosis to family and friends (p = 0.033), and strategies for living with treatment under the best conditions (p = 0.000). Significant differences were found on the topics of cancer (p = 0.000), genetic testing (p = 0.023), therapeutic options (p = 0.000), fatigue following treatment (p = 0.005), pain and discomfort after treatment or surgery (p = 0.000), potential emotions and their management (p = 0.000) and the decision-making processes (p = 0.011). A significant relationship was found between the two groups for patients' ability to cope with cancer (p = 0.038), and their level of psychological distress at different stages of the care pathway (p = 0.024). CONCLUSIONS: This study shows differences between one-time and ongoing support for cancer patients. It highlights the potential for APs to help patients develop self-efficacy and cope with the challenges of cancer treatment.


Assuntos
Neoplasias da Mama , Angústia Psicológica , Humanos , Feminino , Estudos Transversais , Estresse Psicológico/psicologia , Autoeficácia , Adaptação Psicológica , Neoplasias da Mama/terapia , Neoplasias da Mama/psicologia , Inquéritos e Questionários
3.
Eur J Oncol Nurs ; 62: 102256, 2023 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-36634593

RESUMO

OBJECTIVES: In Canada, two out of five people will be diagnosed with cancer which will affect their lives on a physical, psychological, and social levels. To help people affected by cancer (PAC) cope with the disease, support is provided by oncology nurses (ONs), including oncology pivot nurses (OPNs), as well as by accompanying patients (APs), i.e. people who have already had to deal with a cancer problem. APs are still a recent addition to the services offered in oncology, and as of yet no study has explored how the support provided by APs is being integrated into usual care, especially ONs care. This study explores the perceptions of APs and ONs on APs' integration into clinical teams. METHOD: An exploratory qualitative study was carried out with six ONs and six APs through semi-structured interviews conducted from 2020 to 2021. Data were analyzed using a qualitative content analysis. RESULTS: Participants perceived the AP's integration into the teams and during care as variable and in flux. They also identified factors that influence APs' integration into clinical teams (e.g.:the clinical teams' dynamics, the understanding of the AP's role, APs and patients' characteristics). Lastly, participants made recommendations to improve APs integration into clinical teams. CONCLUSION: This study highlights how integrating APs into clinical teams has not yet become part of ONs' routines. ONs can play a key role in their integration through their collaborative and teamwork skills. Furthermore, there is a recognition that these two approaches can play complementary roles in supporting PACs.


Assuntos
Oncologia , Neoplasias , Humanos , Pesquisa Qualitativa , Neoplasias/terapia , Canadá
4.
Health Expect ; 26(2): 847-857, 2023 04.
Artigo em Inglês | MEDLINE | ID: mdl-36704843

RESUMO

INTRODUCTION: Since 2018, four establishments in Quebec, Canada, have decided to implement the PAROLE-Onco programme, which introduced accompanying patients (APs) in healthcare teams to improve the experience of cancer patients. APs are patient advisors who have had a cancer treatment experience and who conduct consultations to complement the service offered by providing emotional, informational and educational support to patients undergoing treatments (e.g., radiotherapy, chemotherapy, surgery), mostly for breast cancer. We aimed to explore the evolution of APs' perspectives regarding their activities within the clinical oncology teams as well as the perceived effects of their intervention with patients, the clinical team and themselves. METHODS: A qualitative study based on semistructured interviews and focus groups was conducted with APs at the beginning of their intervention (T1) and 2 years afterwards (T2). The themes discussed were APs' activities and the perceived effects of their interventions on themselves, on the patients and on the clinical team. RESULTS: In total, 20 APs were interviewed. In T2, APs' activities shifted from listening and sharing experiences to empowering patients by helping them become partners in their care and felt generally more integrated into the clinical team. APs help patients feel understood and supported, alleviate stress and become partners in the care they receive. They also alleviate the clinical team's workload by offering a complementary service through emotional support, which, according to them, helps patients feel calmer and more prepared for their appointments with healthcare professionals. They communicate additional information about their patients' health journey, which makes the appointment more efficient for healthcare professionals. When APs accompany patients, they feel as if they can make a difference in patients' lives. Their activities are perceived by some as an opportunity to give back but also as a way of giving meaning to their own experience, in turn serving as a learning experience. CONCLUSION: By mobilizing their experiential knowledge, APs provide emotional, informational, cognitive and navigational support, which allows patients to be more empowered in their care and which complements professionals' scientific knowledge, thereby helping to refine their sensitivity to the patients' experiences. PATIENT OR PUBLIC CONTRIBUTION: Two patient-researchers have contributed to the study design, the conduct of the study, the data analysis and interpretation, as well as in the preparation and writing of this manuscript.


Assuntos
Neoplasias da Mama , Humanos , Feminino , Neoplasias da Mama/psicologia , Oncologia , Pesquisa Qualitativa , Grupos Focais , Pacientes
5.
Plast Reconstr Surg ; 144(6): 988e-992e, 2019 12.
Artigo em Inglês | MEDLINE | ID: mdl-31764635

RESUMO

Acellular dermal matrices have become a mandatory tool in reconstructive breast surgery. Since their introduction, they have been considered to be nonreactive and nonimmunogenic scaffolds. However, some patients who undergo implant-based breast reconstruction with acellular dermal matrices develop postoperative cutaneous erythema overlying their matrices, a condition commonly referred to as red breast syndrome. The aim of this study was to gain a better understanding of this phenomenon. An analysis was conducted on consecutive patients who underwent acellular dermal matrix- and implant-based breast reconstructions and developed red breast syndrome that was treated surgically between April of 2017 and June of 2018 at the authors' institution. During surgery, 1-cm specimens of acellular dermal matrix were sampled and analyzed by scanning electron microscopy. Observations were charted to score and record the presence and thickness of biofilm, and for identification of bacteria. These measurements were performed using Adobe Photoshop CS6 Extended software. Six postmastectomy breast reconstruction patients were included, all with AlloDerm Ready-to-Use-based reconstructions. All specimens were colonized by various bacteria ranging from Gram-negative bacilli to Gram-positive microorganisms. Biofilm was present in all studied specimens. The cause of skin erythema overlying acellular dermal matrix grafts, and the so-called red breast syndrome, may be related to contamination with various bacteria. Although contamination was omnipresent in analyzed samples, its clinical significance is variable. Even if acellular dermal matrix-based reconstructions are salvaged, this could come at the price of chronic local inflammation.


Assuntos
Derme Acelular/efeitos adversos , Implante Mamário/efeitos adversos , Eritema/microbiologia , Infecções por Bactérias Gram-Negativas/diagnóstico , Infecções por Bactérias Gram-Positivas/diagnóstico , Infecções Relacionadas à Prótese/microbiologia , Adulto , Biofilmes , Implantes de Mama/efeitos adversos , Neoplasias da Mama/cirurgia , Feminino , Humanos , Mastectomia/métodos , Microscopia Eletrônica de Varredura , Pessoa de Meia-Idade
6.
Burns ; 45(5): 1122-1130, 2019 08.
Artigo em Inglês | MEDLINE | ID: mdl-31000317

RESUMO

Biofilm forms when bacteria surrounded by an extracellular matrix aggregate on a surface. It can develop on many surfaces, including wound dressings; this can be particularly nefarious for burn patients undergoing skin grafting (autograft) for burn wound coverage as they often suffer from compromised immune system function. Autograft donor sites are particularly vulnerable to biofilm formation; as such, timely healing of these sites is essential. Our aim was to apply scanning electron microscopy to compare the efficacy of two types of wound dressings in preventing the formation of bacterial biofilm on burn patient skin graft donor sites. One dressing contained bismuth tribromophenate at a concentration of 3% which confers it bacteriostatic properties (Xeroform™). The other was an absorptive alginate calcium sodium dressing (Kaltostat™). Samples of each wound dressing, which were in contact with the skin graft donor site, were prepared for analysis under the scanning electron microscope (SEM) using an original method developed by our research group that aims to maintain the integrity of the biofilm microstructure. Samples prepared by this method were then analyzed using SEM, which allowed the characterization of biofilm and the evaluation of bacterial density on the studied dressing samples. To this day, this imaging technique has been rarely employed for dressing analysis and this is the first time that it is employed for in situ biofilm visualization for this particular application.


Assuntos
Alginatos , Bactérias/ultraestrutura , Bandagens/microbiologia , Biofilmes , Fenóis , Sítio Doador de Transplante/microbiologia , Adulto , Idoso , Feminino , Humanos , Masculino , Microscopia Eletrônica de Varredura , Pessoa de Meia-Idade , Transplante de Pele , Transplante Autólogo , Adulto Jovem
7.
Aesthet Surg J ; 39(11): 1191-1199, 2019 10 15.
Artigo em Inglês | MEDLINE | ID: mdl-30576417

RESUMO

BACKGROUND: Although increasingly reported in the literature, most plastic surgeons cannot define the etiology of double capsules. Often an incidental finding at implant exchange, double capsules are frequently associated with macrotextured devices. Several mechanisms have been proposed, including at the forefront that shearing causes a delamination of the periprosthetic capsule into a double capsule. OBJECTIVES: This study was designed to confirm the hypothesis that mechanical forces are involved in formation of double capsules by histological analysis. METHODS: A prospective analysis of consecutive implants with double capsules removed over 2 years was performed. Data collected at the time of surgery included Baker classification, reason for explant, implant manufacturer and style, and any presence of a seroma associated with the capsule. Specimens were sent for analysis by histology utilizing hematoxylin and eosin and alpha-smooth muscle actin staining techniques. RESULTS: Eight double capsules were collected for specimen analysis. All capsules demonstrated evidence of granulation tissue, alpha-smooth muscle actin positive myofibroblasts, and folds with embedded texture. Fibrosis surrounded weak areas with presence of layering and splitting, creating a potential space that is prone to separation. Tears and folds from granulomatous reaction are also present within the outer layer of the double capsule, which can only be explained by a mechanical shearing force as a pathogenic mechanism. CONCLUSIONS: Understanding the pathogenesis of double capsules may allow plastic surgeons to refine their indications for macrotextured implants while providing guidance to patients on avoidance of activities that produce shear-forces. The findings support the hypothesis that shearing forces delaminate the capsule into 2 separate distinct capsules.


Assuntos
Implante Mamário/efeitos adversos , Implantes de Mama/efeitos adversos , Mama/patologia , Remoção de Dispositivo , Contratura Capsular em Implantes/etiologia , Adulto , Idoso , Mama/cirurgia , Implante Mamário/instrumentação , Feminino , Fibrose , Humanos , Contratura Capsular em Implantes/patologia , Contratura Capsular em Implantes/cirurgia , Pessoa de Meia-Idade , Miofibroblastos , Estudos Prospectivos , Estresse Mecânico , Propriedades de Superfície
9.
Plast Reconstr Surg ; 141(4): 919-928, 2018 04.
Artigo em Inglês | MEDLINE | ID: mdl-29257002

RESUMO

BACKGROUND: Despite benefits in reducing capsular contractures, textured implants have been associated with significant pitfalls, such a propensity for biofilm formation. Few studies have investigated whether the use of acellular dermal matrix on textured implants produces similar findings. This study aims to characterize biofilm formation at the capsular-acellular dermal matrix interface with scanning electron microscopy. METHODS: The authors performed a prospective observational pilot study in patients undergoing two-stage expander-to-permanent implant exchange. Patients were inflated with Biocell or Siltex expanders, and specimens from the capsular-pectoralis interface and capsular-acellular dermal matrix interface were obtained and examined under scanning electron microscopy for capsular ingrowth and biofilm formation using the Van Herdeen Biofilm Grading System and the Biofilm Thickness Grading Scale. RESULTS: Nine patients including 14 breasts (28 capsular samples in total) were examined. Thick biofilm formation was observed in all specimens from the capsular-acellular dermal matrix interface with Biocell and 25 percent of capsule-pectoralis interface, whereas no biofilm formation was found in Siltex implants. For Biocell implants, a significant difference in biofilm coverage between the upper and lower poles was observed using the Van Herdeen Biofilm Grading System (p = 0.0028) and the Biofilm Thickness Grading Scale (p = 0.0161). CONCLUSIONS: Biocell implants produce a significant rate of biofilm formation over acellular dermal matrix-covered capsules, which is not present in the muscular region or in Siltex implants. Further randomized controlled trials will further elucidate the clinical impact of using acellular dermal matrices with macrotextured implants. CLINICAL QUESTION/LEVEL OF EVIDENCE: Therapeutic, IV.


Assuntos
Derme Acelular/microbiologia , Biofilmes , Implante Mamário/instrumentação , Microscopia Eletrônica de Varredura , Dispositivos para Expansão de Tecidos/microbiologia , Expansão de Tecido/instrumentação , Adulto , Idoso , Implante Mamário/métodos , Implantes de Mama , Feminino , Humanos , Pessoa de Meia-Idade , Projetos Piloto , Estudos Prospectivos , Expansão de Tecido/métodos
10.
Biomed Mater ; 13(1): 015005, 2017 Nov 10.
Artigo em Inglês | MEDLINE | ID: mdl-29125132

RESUMO

Platelet-rich plasma (PRP) has been used to treat different orthopedic conditions, however, the clinical benefits of using PRP remain uncertain. Chitosan (CS)-PRP implants have been shown to improve meniscus, rotator cuff and cartilage repair in pre-clinical models. The purpose of this current study was to investigate in vitro and in vivo mechanisms of action of CS-PRP implants. Freeze-dried formulations containing 1% (w/v) CS (80% degree of deacetylation and number average molar mass 38 kDa), 1% (w/v) trehalose as a lyoprotectant and 42.2 mM calcium chloride as a clot activator were solubilized in PRP. Gravimetric measurements and molecular/cellular imaging studies revealed that clot retraction is inhibited in CS-PRP hybrid clots through physical coating of platelets, blood cells and fibrin strands by chitosan, which interferes with platelet aggregation and platelet-mediated clot retraction. Flow cytometry and ELISA assays revealed that platelets are activated and granules secreted in CS-PRP hybrid clots and that cumulative release of platelet-derived growth factor (PDGF-AB) and epidermal growth factor is higher from CS-PRP hybrid clots compared to PRP clots in vitro. Finally, CS-PRP implants resided for up to 6 weeks in a subcutaneous implantation model and induced cell recruitment and granulation tissue synthesis, confirming greater residency and bioactivity compared to PRP in vivo.


Assuntos
Plaquetas/citologia , Quitosana/química , Retração do Coágulo , Fator de Crescimento Derivado de Plaquetas/metabolismo , Plasma Rico em Plaquetas/metabolismo , Animais , Cloreto de Cálcio/química , Fator de Crescimento Epidérmico/metabolismo , Fibrina/química , Citometria de Fluxo , Liofilização , Masculino , Microscopia Confocal , Microscopia Eletrônica de Varredura , Microscopia Eletrônica de Transmissão , Ativação Plaquetária , Agregação Plaquetária , Coelhos , Eletricidade Estática , Temperatura , Fator de Crescimento Transformador beta1/metabolismo
11.
J Pharm Sci ; 105(1): 88-96, 2016 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-26852843

RESUMO

Chitosan/DNA polyplexes have been optimized for efficient and safe in vitro and in vivo gene delivery. Clinical application of this technology requires the development of formulations with higher concentrations to reach therapeutic dosages. Polyplexes were prepared using chitosan and EGFPLuc plasmids. Freeze-thawing and freeze-drying studies were performed to identify and optimize lyoprotectant and buffer contents in formulations. Freeze-dried samples were rehydrated in reduced volumes to increase their final DNA dose. Nanoparticle physicochemical properties were analyzed, and their transfection efficiency and cytotoxicity were measured in human embryonic kidney 293 cells. Data showed that 3.5 mM histidine buffer (pH 6.5) combined with one of 0.5% wt/vol sucrose, dextran 5 kDa, or trehalose was required to prevent polyplex aggregation during freeze-drying. Optimal formulations could be concentrated 20-fold, to a clinically desired ∼1 mg of DNA/mL, while maintaining near physiological pH and tonicity. Polyplexes were predominantly spherical, with diameters below 200 nm, polydispersity indexes below 0.32, and zeta potentials above +19 mV. Rehydrated formulations had transfection efficiencies no less than 65% of fresh polyplexes without excipients and had no effect on viability and metabolic activity of human embryonic kidney 293 cells. These concentrated formulations represent an important step toward clinical use of chitosan-based gene delivery systems.


Assuntos
Quitosana/química , DNA , Portadores de Fármacos/química , Técnicas de Transferência de Genes , Nanopartículas/química , Sobrevivência Celular/efeitos dos fármacos , Quitosana/toxicidade , DNA/administração & dosagem , DNA/genética , Portadores de Fármacos/toxicidade , Liofilização , Proteínas de Fluorescência Verde/genética , Células HEK293 , Humanos , Luciferases/genética , Nanopartículas/toxicidade , Plasmídeos , Polietilenoimina/química , Polietilenoimina/toxicidade , Propriedades de Superfície
12.
Biomaterials ; 67: 65-72, 2015 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-26210173

RESUMO

Breast implants are amongst the most widely used types of permanent implants in modern medicine and have both aesthetic and reconstructive applications with excellent biocompatibility. The double capsule is a complication associated with textured prostheses that leads to implant displacement; however, its etiology has yet to be elucidated. In this study, 10 double capsules were sampled from breast expander implants for in-depth analysis; histologically, the inner capsular layer demonstrated highly organized collagen in sheets with delamination of fibers. At the prosthesis interface (PI) where the implant shell contacts the inner capsular layer, scanning electron microscopy (SEM) revealed a thin layer which mirrored the three-dimensional characteristics of the implant texture; the external surface of the inner capsular layer facing the intercapsular space (ICS) was flat. SEM examination of the inner capsule layer revealed both a large bacterial presence as well as biofilm deposition at the PI; a significantly lower quantity of bacteria and biofilm were found at the ICS interface. These findings suggest that the double capsule phenomenon's etiopathogenesis is of mechanical origin. Delamination of the periprosthetic capsule leads to the creation of the ICS; the maintained separation of the 2 layers subsequently alters the biostability of the macro-textured breast implant.


Assuntos
Implantes de Mama , Processamento de Imagem Assistida por Computador , Biofilmes , Implantes de Mama/microbiologia , Neoplasias da Mama/patologia , Neoplasias da Mama/cirurgia , Cápsulas , Contagem de Colônia Microbiana , Feminino , Humanos , Microscopia Eletrônica de Varredura , Pessoa de Meia-Idade
13.
Plast Reconstr Surg ; 135(4): 967-974, 2015 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-25811562

RESUMO

BACKGROUND: In the first stage of expander-to-implant breast reconstruction, postoperative expansion is classically initiated at 10 to 14 days (conventional approach). The authors hypothesized that it may be beneficial to wait 6 weeks postoperatively before initiating serial expansion (delayed approach). Clinical and ultrastructural periprosthetic capsule analysis is first required before determining whether a delayed approach ultimately improves capsular tissue adherence and expansion process predictability. METHODS: Patients undergoing two-stage implant-based breast reconstruction were enrolled prospectively in this study. During expander-to-implant exchange, the clinical presence of "Velcro" effect, biofilm, and double capsule was noted. Periprosthetic capsule samples were also sent for scanning electron microscopic observation of three parameters: surface relief, cellularity, and biofilm. Samples were divided into four groups for data analysis (group 1, conventional/Biocell; group 2, delayed/Biocell; group 3, conventional/Siltex; and group 4, delayed/Siltex). RESULTS: Fifty-six breast reconstructions were included. Each group comprised between 13 and 15 breasts. In group 1, no cases exhibited the Velcro effect and there was a 53.8 percent incidence of both biofilm and double capsule. In group 2, all cases demonstrated the Velcro effect and there were no incidences of biofilm or double capsule. Group 3 and group 4 cases did not exhibit a Velcro effect or double-capsule formation; however, biofilm was present in up to 20.0 percent. All group 2 samples revealed more pronounced three-dimensional relief on scanning electron microscopy. CONCLUSIONS: Variations in expansion protocols can lead to observable modifications in periprosthetic capsular architecture. There may be real benefits to delaying expander inflation until 6 weeks postoperatively with Biocell expanders.


Assuntos
Implante Mamário/métodos , Implantes de Mama , Neoplasias da Mama/cirurgia , Mama/cirurgia , Mama/ultraestrutura , Dispositivos para Expansão de Tecidos , Expansão de Tecido , Feminino , Humanos , Contratura Capsular em Implantes/patologia , Microscopia Eletrônica de Varredura , Pessoa de Meia-Idade , Período Pós-Operatório , Estudos Prospectivos , Fatores de Tempo
14.
Eur J Pharm Sci ; 45(1-2): 138-49, 2012 Jan 23.
Artigo em Inglês | MEDLINE | ID: mdl-22085632

RESUMO

Glucagon like peptide 1 (GLP-1), a blood glucose homeostasis modulating incretin, has been proposed for the treatment of type 2 diabetes mellitus (T2DM). However, native GLP-1 pharmacokinetics reveals low bioavailability due to degradation by the ubiquitous dipeptydil peptidase IV (DPP-IV) endoprotease. In this study, the glucosamine-based polymer chitosan was used as a cationic polymer-based in vitro delivery system for GLP-1, DPP-IV resistant GLP-1 analogues and siRNA targeting DPP-IV mRNA. We found chitosans to form spherical nanocomplexes with these nucleic acids, generating two distinct non-overlapping size ranges of 141-283 nm and 68-129 nm for plasmid and siRNA, respectively. The low molecular weight high DDA chitosan 92-10-5 (degree of deacetylation, molecular weight and N:P ratio (DDA-Mn-N:P)) showed the highest plasmid DNA transfection efficiency in HepG2 and Caco-2 cell lines when compared to 80-10-10 and 80-80-5 chitosans. Recombinant native GLP-1 protein levels in media of transfected cells reached 23 ng/L while our DPP-IV resistant analogues resulted in a fivefold increase of GLP-1 protein levels (115 ng/L) relative to native GLP-1, and equivalent to the Lipofectamine positive control. We also found that all chitosan-DPP-IV siRNA nanocomplexes were capable of DPP-IV silencing, with 92-10-5 being significantly more effective in abrogating enzymatic activity of DPP-IV in media of silenced cells, and with no apparent cytotoxicity. These results indicate that specific chitosan formulations may be effectively used for the delivery of plasmid DNA and siRNA in a combination therapy of type 2 diabetes.


Assuntos
Quitosana/química , Inibidores da Dipeptidil Peptidase IV/metabolismo , Inativação Gênica , Técnicas de Transferência de Genes , Peptídeo 1 Semelhante ao Glucagon/análogos & derivados , Nanopartículas/química , RNA Interferente Pequeno/metabolismo , Acetilação , Células CACO-2 , Fenômenos Químicos , Quitosana/efeitos adversos , Diabetes Mellitus Tipo 2/genética , Diabetes Mellitus Tipo 2/terapia , Dipeptidil Peptidase 4/química , Dipeptidil Peptidase 4/genética , Dipeptidil Peptidase 4/metabolismo , Inibidores da Dipeptidil Peptidase IV/administração & dosagem , Inibidores da Dipeptidil Peptidase IV/química , Terapia Genética/métodos , Peptídeo 1 Semelhante ao Glucagon/genética , Peptídeo 1 Semelhante ao Glucagon/metabolismo , Peptídeo 1 Semelhante ao Glucagon/uso terapêutico , Células HT29 , Células Hep G2 , Humanos , Peso Molecular , Nanopartículas/efeitos adversos , Nanopartículas/ultraestrutura , Tamanho da Partícula , RNA Interferente Pequeno/administração & dosagem , RNA Interferente Pequeno/química , Proteínas Recombinantes de Fusão/genética , Proteínas Recombinantes de Fusão/metabolismo , Proteínas Recombinantes de Fusão/uso terapêutico , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Proteínas Recombinantes/uso terapêutico
15.
J Orthop Res ; 27(9): 1197-203, 2009 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-19242978

RESUMO

Meniscus injury is a frequently encountered clinical orthopedic issue and is epidemiologically correlated to osteoarthritis. The development of new treatments for meniscus injury is intimately related to the appropriateness of animal models for their investigation. The purpose of this study was to structurally compare human menisci to sheep and rabbit menisci to generate pertinent animal models for meniscus repair. Menisci were analyzed histologically, immunohistochemically, and by environmental scanning electron microscopy (ESEM). In all species, collagen I appeared throughout most menisci, but was absent from the inner portion of the tip in some samples. Collagen II was present throughout the inner main meniscal body, while collagen VI was found in pericellular and perivascular regions. The glycosaminoglycan-rich inner portion of menisci was greater in area for rabbit and sheep compared to human. Cells were rounded in central regions and more fusiform at the surface, with rabbit being more cellular than sheep and human. Vascular penetration in rabbit was confined to the very outermost region (1% of meniscus length), while vessels penetrated deeper into sheep and human menisci (11-15%). ESEM revealed a lamellar collagenous structure at the articulating surfaces of sheep and human menisci that was absent in rabbit. Taken together, these data suggest that the main structural features that will influence meniscus repair-cellularity, vascularity, collagen structure-are similar in sheep and human but significantly different in rabbit, motivating the development of ovine meniscus repair models.


Assuntos
Traumatismos do Joelho/patologia , Traumatismos do Joelho/cirurgia , Meniscos Tibiais , Animais , Colágeno Tipo I/metabolismo , Colágeno Tipo II/metabolismo , Colágeno Tipo VI/metabolismo , Modelos Animais de Doenças , Matriz Extracelular/metabolismo , Matriz Extracelular/patologia , Matriz Extracelular/ultraestrutura , Glicosaminoglicanos/metabolismo , Humanos , Meniscos Tibiais/patologia , Meniscos Tibiais/cirurgia , Microscopia Eletrônica de Varredura , Pessoa de Meia-Idade , Coelhos , Regeneração/fisiologia , Especificidade da Espécie , Lesões do Menisco Tibial
16.
J Biol Chem ; 283(46): 31522-30, 2008 Nov 14.
Artigo em Inglês | MEDLINE | ID: mdl-18723503

RESUMO

Isolated chondrocytes form aggregates in suspension culture that maintain chondrocyte phenotype in a physiological pericellular environment. The molecular mechanisms involved in chondrocyte aggregation have not been previously identified. Using this novel suspension culture system, we performed mRNA and protein expression analysis along with immunohistochemistry for potential cell adhesion molecules and extracellular matrix integrin ligands. Inhibition of aggregation assays were performed using specific blocking agents. We found that: (i) direct cell-cell interactions were not involved in chondrocyte aggregation, (ii) chondrocytes in aggregates were surrounded by a matrix rich in collagen II and cartilage oligomeric protein (COMP), (iii) aggregation depends on a beta1-integrin, which binds a triple helical GFOGER sequence found in collagens, (iv) integrin alpha10-subunit is the most highly expressed alpha-subunit among those tested, including alpha5, in aggregating chondrocytes. Taken together, this body of evidence suggests that the main molecular interaction involved in aggregation of phenotypically stable chondrocytes is the alpha10beta1-collagen II interaction.


Assuntos
Técnicas de Cultura de Células/métodos , Condrócitos/citologia , Condrócitos/metabolismo , Colágeno/metabolismo , Integrina beta1/metabolismo , Fragmentos de Peptídeos/metabolismo , Sequência de Aminoácidos , Animais , Caderinas/metabolismo , Cálcio/química , Cálcio/metabolismo , Bovinos , Agregação Celular , Células Cultivadas , Condrócitos/ultraestrutura , Colágeno/química , Íons/química , Microscopia Eletrônica de Varredura , Moléculas de Adesão de Célula Nervosa/metabolismo , Fragmentos de Peptídeos/química , Fenótipo , Estrutura Secundária de Proteína , Subunidades Proteicas/metabolismo , Sefarose , Trombospondinas/metabolismo
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