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1.
Psychol Trauma ; 2024 Jun 27.
Artigo em Inglês | MEDLINE | ID: mdl-38934934

RESUMO

OBJECTIVE: Demand for trauma-focused therapy continues to increase, especially in community mental health care settings where group treatment models can be cost-effective and increase access to care. The Internal Family Systems (IFS) model for posttraumatic stress disorder (PTSD) may offer an effective therapeutic approach. The purpose of this proof-of-concept study was to evaluate the feasibility and acceptability of a novel, trauma-focused, group-based treatment approach and investigate potential mechanisms of action. METHOD: Study participants completed the Program for Alleviating and Resolving Trauma and Stress (PARTS), an online-delivered program including 16 weeks of 90-min IFS-based groups with eight 50-min individual IFS counseling sessions. Participants completed assessments including clinician-administered and self-report measures of PTSD, common comorbid conditions (e.g., complex PTSD [disturbances in self-organization], depression, anxiety, and suicidality), and potential mechanisms (e.g., decentering, self-compassion, and emotion regulation). RESULTS: Most participants (n = 11/15; 73%) attended 12+ group sessions, with 92% (12/13 responders) reporting they would recommend PARTS to a friend. All respondents reported the program was helpful (13/13; 100%). PTSD symptom severity was reduced from baseline to Weeks 16 (d = -0.7, p = .005) and 24 (d = -0.9, p < .001). A clinically meaningful response (i.e., 10+ point reduction on the Clinician-Administered PTSD Scale for Diagnostic and Statistical Manual of Mental Disorders [5th ed.]) was demonstrated in 53% of participants (8/15) by Week 24. Decentering, self-compassion, and emotion regulation all improved (p < .05). CONCLUSIONS: PARTS was feasible and acceptable as a group-based, online intervention in an urban, public community health care system. While PARTS showed promise in reducing overall PTSD symptom severity, well-controlled efficacy research is needed. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

2.
Cell Death Discov ; 7(1): 56, 2021 Mar 17.
Artigo em Inglês | MEDLINE | ID: mdl-33731692

RESUMO

The goal of this study was to determine whether recombinant Islet NeoGenesis Associated Protein (rINGAP) and its active core, a pentadecapeptide INGAP104-118 (Ingap-p), protect ß cells against cytokine-induced death. INGAP has been shown to induce islet neogenesis in diabetic animals, to stimulate ß-cell proliferation and differentiation, and to improve islet survival and function. Importantly, Ingap-p has shown promising results in clinical trials for diabetes (phase I/II). However, the full potential of INGAP and its mechanisms of action remain poorly understood. Using rat insulinoma cells RINm5F and INS-1 treated with interleukin-1ß (IL-1ß) and interferon-gamma (IFN-γ), we demonstrate here that both rINGAP and Ingap-p inhibit apoptosis, Caspase-3 activation, inducible nitric oxide synthase (iNOS) expression and nitric oxide (NO) production, and explore the related signaling pathways. As expected, IL-1ß induced nuclear factor kappa B (NF-κB), p38, and JNK signaling, whereas interferon-gamma (IFN-γ) activated the JAK2/STAT1 pathway and potentiated the IL-1ß effects. Both rINGAP and Ingap-p decreased phosphorylation of IKKα/ß, IkBα, and p65, although p65 nuclear translocation was not inhibited. rINGAP, used for further analysis, also inhibited STAT3, p38, and JNK activation. Interestingly, all inhibitory effects of rINGAP were observed for the cytokine cocktail, not IL-1ß alone, and were roughly equal to reversing the potentiating effects of INFγ. Furthermore, rINGAP had no effect on IL-1ß/NF-κB-induced gene expression (e.g., Ccl2, Sod2) but downregulated several IFNγ-stimulated (Irf1, Socs1, Socs3) or IFNγ-potentiated (Nos2) genes. This, however, was observed again only for the cytokine cocktail, not IFNγ alone, and rINGAP did not inhibit the IFNγ-induced JAK2/STAT1 activation. Together, these intriguing results suggest that INGAP does not target either IL-1ß or IFNγ individually but rather inhibits the signaling crosstalk between the two, the exact mechanism of which remains to be investigated. In summary, our study characterizes the anti-inflammatory effects of INGAP, both protein and peptide, and suggests a new therapeutic utility for INGAP in the treatment of diabetes.

3.
J Cell Mol Med ; 23(4): 2890-2900, 2019 04.
Artigo em Inglês | MEDLINE | ID: mdl-30710421

RESUMO

Both type 2 diabetes (T2D) and obesity are characterized by excessive hyperlipidaemia and subsequent lipid droplet (LD) accumulation in adipose tissue. To investigate whether LDs also accumulate in ß-cells of T2D patients, we assessed the expression of PLIN2, a LD-associated protein, in non-diabetic (ND) and T2D pancreata. We observed an up-regulation of PLIN2 mRNA and protein in ß-cells of T2D patients, along with significant changes in the expression of lipid metabolism, apoptosis and oxidative stress genes. The increased LD buildup in T2D ß-cells was accompanied by inhibition of nuclear translocation of TFEB, a master regulator of autophagy and by down-regulation of lysosomal biomarker LAMP2. To investigate whether LD accumulation and autophagy were influenced by diabetic conditions, we used rat INS-1 cells to model the effects of hyperglycaemia and hyperlipidaemia on autophagy and metabolic gene expression. Consistent with human tissue, both LD formation and PLIN2 expression were enhanced in INS-1 cells under hyperglycaemia, whereas TFEB activation and autophagy gene expression were significantly reduced. Collectively, these results suggest that lipid clearance and overall homeostasis is markedly disrupted in ß-cells under hyperglycaemic conditions and interventions ameliorating lipid clearance could be beneficial in reducing functional impairments in islets caused by glucolipotoxicity.


Assuntos
Autofagia , Diabetes Mellitus Tipo 2/fisiopatologia , Regulação da Expressão Gênica , Hiperglicemia/patologia , Hiperlipidemias/patologia , Células Secretoras de Insulina/patologia , Lipídeos/análise , Animais , Apoptose , Fatores de Transcrição de Zíper de Leucina e Hélice-Alça-Hélix Básicos/genética , Fatores de Transcrição de Zíper de Leucina e Hélice-Alça-Hélix Básicos/metabolismo , Estudos de Casos e Controles , Diabetes Mellitus Tipo 2/complicações , Diabetes Mellitus Tipo 2/metabolismo , Humanos , Hiperglicemia/etiologia , Hiperglicemia/metabolismo , Hiperlipidemias/etiologia , Hiperlipidemias/metabolismo , Células Secretoras de Insulina/metabolismo , Insulinoma/genética , Insulinoma/metabolismo , Insulinoma/patologia , Proteína 2 de Membrana Associada ao Lisossomo/genética , Proteína 2 de Membrana Associada ao Lisossomo/metabolismo , Lisossomos/metabolismo , Lisossomos/patologia , Neoplasias Pancreáticas/genética , Neoplasias Pancreáticas/metabolismo , Neoplasias Pancreáticas/patologia , Perilipina-2/genética , Perilipina-2/metabolismo , Ratos , Células Tumorais Cultivadas
4.
Healthc Pap ; 17(4): 32-40, 2018 04.
Artigo em Inglês | MEDLINE | ID: mdl-30291708

RESUMO

In hindsight, there have been unintended systemic consequences stemming from the traditional roles physicians have assumed and the structures within which they have been permitted to organize themselves. It is critical that the national discussion take account of this because we must reconcile ourselves to the current reality in which all other allied healthcare professionals are practising at "the top of their licence." Furthermore, the pace of technological change, especially the deciphering of the genome and the digitalization of virtually everything, has engendered a revolution characterized by the democratization of knowledge and technology, so that the point of care will be wherever the patient is. Dysfunctional reimbursement schemes and a lack of accountability are merely symptoms of a system that must change.


Assuntos
Atenção à Saúde/métodos , Reforma dos Serviços de Saúde , Médicos , Responsabilidade Social , Humanos , Quebeque
5.
Surgery ; 160(4): 1118-1124, 2016 10.
Artigo em Inglês | MEDLINE | ID: mdl-27521046

RESUMO

BACKGROUND: We developed a high efficiency endocrine operative protocol based on a mathematical programming approach, process reengineering, and value-stream mapping to increase the number of operations completed per day without increasing operating room time at a tertiary-care, academic center. METHODS: Using this protocol, a case-control study of 72 patients undergoing endocrine operation during high efficiency days were age, sex, and procedure-matched to 72 patients undergoing operation during standard days. The demographic profile, operative times, and perioperative complications were noted. RESULTS: The average number of cases per 8-hour workday in the high efficiency and standard operating rooms were 7 and 5, respectively. Mean procedure times in both groups were similar. The turnaround time (mean ± standard deviation) in the high efficiency group was 8.5 (±2.7) minutes as compared with 15.4 (±4.9) minutes in the standard group (P < .001). Transient postoperative hypocalcemia was 6.9% (5/72) and 8.3% (6/72) for the high efficiency and standard groups, respectively (P = .99). CONCLUSION: In this study, patients undergoing high efficiency endocrine operation had similar procedure times and perioperative complications compared with the standard group. The proposed high efficiency protocol seems to better utilize operative time and decrease the backlog of patients waiting for endocrine operation in a country with a universal national health care program.


Assuntos
Salas Cirúrgicas/organização & administração , Duração da Cirurgia , Paratireoidectomia/normas , Complicações Pós-Operatórias/prevenção & controle , Avaliação de Processos em Cuidados de Saúde , Tireoidectomia/normas , Centros Médicos Acadêmicos/normas , Adulto , Canadá , Estudos de Casos e Controles , Eficiência Organizacional , Feminino , Humanos , Tempo de Internação , Masculino , Pessoa de Meia-Idade , Modelos Teóricos , Paratireoidectomia/tendências , Assistência Perioperatória , Complicações Pós-Operatórias/epidemiologia , Padrões de Referência , Tireoidectomia/tendências , Listas de Espera
7.
Differentiation ; 90(4-5): 77-90, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-26558987

RESUMO

Regeneration of ß-cells in diabetic patients is an important goal of diabetes research. Islet Neogenesis Associated Protein (INGAP) was discovered in the partially duct-obstructed hamster pancreas. Its bioactive fragment, pentadecapeptide 104-118 (INGAP-P), has been shown to reverse diabetes in animal models and to improve glucose homeostasis in patients with diabetes in clinical trials. Further development of INGAP as a therapy for diabetes requires identification of target cells in the pancreas and characterization of the mechanisms of action. We hypothesized that adult human pancreatic ductal cells retain morphogenetic plasticity and can be induced by INGAP to undergo endocrine differentiation. To test this hypothesis, we treated the normal human pancreatic ductal cell line (HPDE) with either INGAP-P or full-length recombinant protein (rINGAP) for short-term periods. Our data show that this single drug treatment induces both proliferation and transdifferentiation of HPDE cells, the latter being characterized by the rapid sequential activation of endocrine developmental transcription factors Pdx-1, Ngn3, NeuroD, IA-1, and MafA and subsequently the expression of insulin at both the mRNA and the protein levels. After 7 days, C-peptide was detected in the supernatant of INGAP-treated cells, reflecting their ability to secrete insulin. The magnitude of differentiation was enhanced by embedding the cells in Matrigel, which led to islet-like cluster formation. The islet-like clusters cells stained positive for nuclear Pdx-1 and Glut 2 proteins, and were expressing Insulin mRNA. These new data suggest that human adult pancreatic ductal cells retain morphogenetic plasticity and demonstrate that a short exposure to INGAP triggers their differentiation into insulin-expressing cells in vitro. In the context of the urgent search for a regenerative and/or cellular therapy for diabetes, these results make INGAP a promising therapeutic candidate.


Assuntos
Antígenos de Neoplasias/farmacologia , Biomarcadores Tumorais/farmacologia , Peptídeo C/metabolismo , Proliferação de Células/efeitos dos fármacos , Transdiferenciação Celular/efeitos dos fármacos , Citocinas/farmacologia , Diabetes Mellitus/terapia , Insulina/metabolismo , Fragmentos de Peptídeos/farmacologia , Fatores de Transcrição/fisiologia , Adulto , Animais , Antígenos de Neoplasias/genética , Biomarcadores Tumorais/genética , Linhagem Celular , Colágeno/farmacologia , Cricetinae , Combinação de Medicamentos , Humanos , Secreção de Insulina , Células Secretoras de Insulina/metabolismo , Laminina/farmacologia , Lectinas Tipo C/genética , Ductos Pancreáticos , Proteínas Associadas a Pancreatite , Proteoglicanas/farmacologia , Proteínas Recombinantes/farmacologia
8.
Stem Cell Res Ther ; 6: 225, 2015 Nov 23.
Artigo em Inglês | MEDLINE | ID: mdl-26597928

RESUMO

Human mesenchymal stem cells (hMSCs), also called mesenchymal stromal cells, have been of great interest in regenerative medicine applications because of not only their differentiation potential but also their ability to secrete bioactive factors that can modulate the immune system and promote tissue repair. This potential has initiated many early-phase clinical studies for the treatment of various diseases, disorders, and injuries by using either hMSCs themselves or their secreted products. Currently, hMSCs for clinical use are generated through conventional static adherent cultures in the presence of fetal bovine serum or human-sourced supplements. However, these methods suffer from variable culture conditions (i.e., ill-defined medium components and heterogeneous culture environment) and thus are not ideal procedures to meet the expected future demand of quality-assured hMSCs for human therapeutic use. Optimizing a bioprocess to generate hMSCs or their secreted products (or both) promises to improve the efficacy as well as safety of this stem cell therapy. In this review, current media and methods for hMSC culture are outlined and bioprocess development strategies discussed.


Assuntos
Técnicas de Cultura de Células , Células-Tronco Mesenquimais , Animais , Reatores Biológicos , Humanos , Células-Tronco Mesenquimais/metabolismo
10.
Am J Physiol Endocrinol Metab ; 303(7): E917-27, 2012 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-22850686

RESUMO

Islet neogenesis-associated protein (INGAP) was discovered in the partially duct-obstructed hamster pancreas as a factor inducing formation of new duct-associated islets. A bioactive portion of INGAP, INGAP(104-118) peptide (INGAP-P), has been shown to have neogenic and insulin-potentiating activity in numerous studies, including recent phase 2 clinical trials that demonstrated improved glucose homeostasis in both type 1 and type 2 diabetic patients. Aiming to improve INGAP-P efficacy and to understand its mechanism of action, we cloned the full-length protein (rINGAP) and compared the signaling events induced by the protein and the peptide in RIN-m5F cells that respond to INGAP with an increase in proliferation. Here, we show that, although both rINGAP and INGAP-P signal via the Ras/Raf/ERK pathway, rINGAP is at least 100 times more efficient on a molar basis than INGAP-P. For either ligand, ERK1/2 activation appears to be pertussis toxin sensitive, suggesting involvement of a G protein-coupled receptor(s). However, there are clear differences between the peptide and the protein in interactions with the cell surface and in the downstream signaling. We demonstrate that fluorescent-labeled rINGAP is characterized by clustering on the membrane and by slow internalization (≤5 h), whereas INGAP-P does not cluster and is internalized within minutes. Signaling by rINGAP appears to involve Src, in contrast to INGAP-P, which appears to activate Akt in addition to the Ras/Raf/ERK1/2 pathway. Thus our data suggest that interactions of INGAP with the cell surface are important to consider for further development of INGAP as a pharmacotherapy for diabetes.


Assuntos
Antígenos de Neoplasias/farmacologia , Biomarcadores Tumorais/farmacologia , Citocinas/farmacologia , Ilhotas Pancreáticas/efeitos dos fármacos , Fragmentos de Peptídeos/farmacologia , Proteínas Recombinantes/farmacologia , Animais , Linhagem Celular , Proliferação de Células/efeitos dos fármacos , Clonagem Molecular , Lectinas Tipo C , Proteínas Associadas a Pancreatite , Toxina Pertussis/farmacologia , Ratos , Transdução de Sinais/efeitos dos fármacos
11.
Phys Med Biol ; 57(16): 5097-112, 2012 Aug 21.
Artigo em Inglês | MEDLINE | ID: mdl-22837013

RESUMO

In this study, we introduce a cellular differentiation cellular model based on dielectric spectroscopy that characterizes epithelial differentiation processes. Non-invasive cellular monitoring was achieved within a three-dimensional microenvironment consisting of a cell-containing collagen I gel seeded onto microfabricated scaffolds. In this proof-of-concept investigation, Madin-Darby canine kidney cells were cultured within microfabricated, geometrically controlled scaffolds and allowed us to differentiate to hollow cyst-like structures. This transformation within the three-dimensional environment is monitored and characterized through dielectric spectroscopy while maintaining cell culture in vitro.


Assuntos
Diferenciação Celular , Espectroscopia Dielétrica , Células Epiteliais/citologia , Alicerces Teciduais , Animais , Membrana Basal/citologia , Técnicas de Cultura de Células , Proliferação de Células , Cães , Análise de Elementos Finitos , Junções Comunicantes/metabolismo , Células Madin Darby de Rim Canino
13.
Stem Cells Int ; 2012: 123030, 2012.
Artigo em Inglês | MEDLINE | ID: mdl-22645619

RESUMO

Human mesenchymal stem cells (hMSCs) are presently being evaluated for their therapeutic potential in clinical studies to treat various diseases, disorders, and injuries. To date, early-phase studies have indicated that the use of both autologous and allogeneic hMSCs appear to be safe; however, efficacy has not been demonstrated in recent late-stage clinical trials. Optimized cell bioprocessing protocols may enhance the efficacy as well as safety of hMSC therapeutics. Classical media used for generating hMSCs are typically supplemented with ill-defined supplements such as fetal bovine serum (FBS) or human-sourced alternatives. Ideally, culture media are desired to have well-defined serum-free formulations that support the efficient production of hMSCs while maintaining their therapeutic and differentiation capacity. Towards this objective, we review here current cell culture media for hMSCs and discuss medium development strategies.

15.
Biotechnol Appl Biochem ; 59(2): 106-20, 2012.
Artigo em Inglês | MEDLINE | ID: mdl-23586791

RESUMO

Human mesenchymal stem cells (hMSCs) have many potential applications in tissue engineering and regenerative medicine. Currently, hMSCs are generated through conventional static adherent cultures in the presence of fetal bovine serum (FBS) for clinical applications (e.g., multiple sclerosis). However, these methods are not appropriate to meet the expected future demand for quality-assured hMSCs for human therapeutic use. Hence, it is imperative to develop an effective hMSC production system, which should be controllable, reproducible, and scalable. To this end, efforts have been made by several international research groups to develop (i) alternative media either by replacing FBS with human-sourced supplements (such as human serum or platelet lysate) or by identifying defined serum-free formulations consisting of key growth/attachment factors, and (ii) controlled bioreactor protocols. In this regard, we review here current hMSC production technologies and future perspectives toward efficient methods for the generation of clinically relevant numbers of hMSC therapeutics.


Assuntos
Técnicas de Cultura de Células/métodos , Células-Tronco Mesenquimais/citologia , Biotecnologia/métodos , Meios de Cultura , Humanos
16.
J Tissue Eng Regen Med ; 6(5): 391-403, 2012 May.
Artigo em Inglês | MEDLINE | ID: mdl-21744510

RESUMO

Human mesenchymal stem cells (hMSCs) are typically obtained for research or therapeutic applications by isolating and subculturing adherent cells from bone marrow on tissue-culture substrates using growth media. The purity and properties of the resulting populations can be affected greatly by the conditions under which they are cultured. Fetal bovine serum (FBS), although ill-defined, has been widely used as a critical requirement for conventional hMSC culture. However, a defined serum-free medium would greatly facilitate the development of robust, clinically acceptable bioprocesses for reproducibly generating quality-assured cells. The present study provides evidence demonstrating that a defined serum-free medium (PPRF-msc6) shows several beneficial features over a conventional FBS-containing medium for the production of hMSCs. When compared to control FBS-based cultures, PPRF-msc6 medium supported the derivation of hMSCs from primary cultures of bone marrow cells in a more rapid and consistent manner. Furthermore, hMSCs cultured in PPRF-msc6 exhibited: (a) a greater colony-forming capacity in primary as well as passaged cultures; (b) negligible lag phase and explicit exponential growth; (c) lower population doubling times (21-26 h vs 35-38 h between passage levels 1 and 10); (d) a greater number of population doublings (62 ± 4 vs 43 ± 2; over a 2 month period); and (e) a higher degree of homogeneity in size. Our data demonstrate that PPRF-msc6 is an important development which opens the door for the rapid, efficient and reproducible production of hMSCs in clinical settings.


Assuntos
Técnicas de Cultura de Células/métodos , Separação Celular , Meios de Cultura Livres de Soro/química , Células-Tronco Mesenquimais/citologia , Células-Tronco Mesenquimais/metabolismo , Animais , Bovinos , Células Cultivadas , Meios de Cultura Livres de Soro/farmacologia , Humanos
17.
J Diabetes Mellitus ; 2(2): 251-257, 2012 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-26473085

RESUMO

Type 1 diabetes mellitus results from the autoimmune and inflammatory destruction of insulin-producing islet ß cells, rendering individuals devoid of insulin production. Recent studies suggest that combination therapies consisting of anti-inflammatory agents and islet growth-promoting factors have the potential to cause sustained recovery of ß cell mass, leading to amelioration or reversal of type 1 diabetes in mouse models. In this study, we hypothesized that the combination of the anti-inflammatory agent lisofylline (LSF) with an active peptide fragment of islet neogenesis associated protein (INGAP peptide) would lead to remission of type 1 diabetes in the non-obese diabetic (NOD) mouse. We treated groups of spontaneously diabetic NOD mice with combinations of LSF, INGAP peptide, or control saline parenterally for up to 6 weeks. Our results demonstrate that the mice receiving combined treatment with LSF and INGAP peptide exhibited partial remission of diabetes with increased plasma insulin levels. Histologic assessment of pancreata in mice receiving combined therapy revealed the presence of islet insulin staining, increased ß cell replication, and evidence of Pdx1-positivity in ductal cells. By contrast, diabetic animals showed severe insulitis with no detectible insulin or Pdx1 staining. We conclude that the novel combination treatment with LSF and INGAP peptide has the potential to ameliorate hyperglycemia in the setting of established type 1 diabetes via the recovery of endogenous ß cells and warrant further studies.

18.
J Endocrinol ; 211(3): 231-9, 2011 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-21933872

RESUMO

Given the inherent therapeutic potential of the morphogenetic plasticity of adult human islets, the identification of factors controlling their cellular differentiation is of interest. The epidermal growth factor (EGF) family has been identified previously in the context of pancreatic organogenesis. We examined the role of EGF in an in vitro model whereby adult human islets are embedded in a collagen gel and dedifferentiated into duct-like epithelial structures (DLS). We demonstrated that DLS formation was EGF dependent, while residual DLS formation in the absence of added EGF was abrogated by EGF receptor inhibitor treatment. With respect to signaling, EGF administration led to an increase in c-Jun NH2-terminal kinase (JNK) phosphorylation early in DLS formation and in AKT and extracellular signal-regulated kinase (ERK) phosphorylation late in the process of DLS formation, concomitant with the increased proliferation of dedifferentiated cells. In the absence of EGF, these phosphorylation changes are not seen and the typical increase in DLS epithelial cell proliferation seen after 10 days in culture is attenuated. Thus, in our model, EGF is necessary for islet cell dedifferentiation, playing an important role in both the onset of DLS formation (through JNK) and in the proliferation of these dedifferentiated cells (through AKT and ERK).


Assuntos
Desdiferenciação Celular/efeitos dos fármacos , Fator de Crescimento Epidérmico/farmacologia , Ilhotas Pancreáticas/citologia , Ilhotas Pancreáticas/efeitos dos fármacos , Adulto , Sequência de Bases , Desdiferenciação Celular/genética , Desdiferenciação Celular/fisiologia , Primers do DNA/genética , Fator de Crescimento Epidérmico/metabolismo , Receptores ErbB/antagonistas & inibidores , Receptores ErbB/genética , Feminino , Expressão Gênica , Humanos , Técnicas In Vitro , Ilhotas Pancreáticas/metabolismo , Proteínas Quinases JNK Ativadas por Mitógeno/metabolismo , Ligantes , Masculino , Pessoa de Meia-Idade , Quinases de Proteína Quinase Ativadas por Mitógeno/metabolismo , Fosforilação , Proteínas Proto-Oncogênicas c-akt/metabolismo , Transdução de Sinais/efeitos dos fármacos
19.
Endocrinology ; 152(2): 424-35, 2011 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-21177833

RESUMO

ß1-integrin is a well-established regulator of ß-cell activities; however, the role of its associated α-subunits is relatively unknown. Previously, we have shown that human fetal islet and INS-1 cells highly express α3ß1-integrin and that collagens I and IV significantly enhance their survival and function; in addition, blocking ß1 function in the fetal islet cells decreased adhesion on collagen I and increased apoptosis. The present study investigates the effect of blocking α3. Using α3 blocking antibody or small interfering RNA, the effects of α3-integrin blockade were examined in isolated human fetal or adult islet cells or INS-1 cells, cultured on collagens I or IV. In parallel, ß1 blockade was analyzed in INS-1 cells. Perturbing α3 function in human islet or INS-1 cells resulted in significant decreases in cell function (adhesion, spreading, proliferation and Pdx1 and insulin expression/secretion), primarily on collagen IV. A significant decrease in focal adhesion kinase and ERK1/2 phosphorylation and increased caspase3 cleavage were observed on both collagens. These effects were similar to changes after ß1 blockade. Interestingly, only α3 blockade reduced expression of phospho-Akt and members of its downstream signaling cascades (glycogen synthase kinase ß and X-linked inhibitor of apoptosis), demonstrating a specific effect of α3 on the phosphatidylinositol 3-kinase/Akt pathway. These results suggest that α3- as well as ß1-integrin-extracellular matrix interactions are critical for modulating ß-cell survival and function through specialized signaling cascades and enhance our understanding of how to improve islet microenvironments for cell-based treatments of diabetes.


Assuntos
Integrina alfa3/metabolismo , Integrina beta1/metabolismo , Ilhotas Pancreáticas/efeitos dos fármacos , Ilhotas Pancreáticas/metabolismo , Fosfatidilinositol 3-Quinase/metabolismo , Proteínas Proto-Oncogênicas c-akt/metabolismo , Transdução de Sinais/efeitos dos fármacos , Idoso , Androstadienos/farmacologia , Animais , Anticorpos/farmacologia , Western Blotting , Butadienos/farmacologia , Linhagem Celular , Imunofluorescência , Humanos , Técnicas In Vitro , Integrina alfa3/genética , Integrina alfa3/imunologia , Integrina beta1/genética , Integrina beta1/imunologia , Ilhotas Pancreáticas/citologia , Pessoa de Meia-Idade , Nitrilas/farmacologia , Inibidores de Fosfoinositídeo-3 Quinase , Ratos , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Transdução de Sinais/genética , Wortmanina
20.
Biomaterials ; 32(6): 1536-42, 2011 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-21093908

RESUMO

Human pancreatic islet in vitro culture is very challenging and requires the presence of various extra cellular matrix (ECM) components in a three-dimensional environment, which provides mechanical and biological support. The development of such an environment is vital in providing favourable conditions to preserve human islets in long-term culture. In this study, we investigated the effects of human islet culture within various three-dimensional environments; collagen I gel, collagen I gel supplemented with ECM components fibronectin and collagen IV, and microfabricated scaffold with ECM-supplemented gel. The cultured human islets were analyzed for functionality, gene expression and hormone content following long-term in vitro culture. It was clear the incorporation of ECM components within the three-dimensional support improved prolonged culture. However, long-term and highly uniform human islet culture within a microfabricated scaffold, with controlled pore structures, coupled with the presence of ECM components, displayed an insulin release profile similar to freshly isolated islets, yielding a stimulation index of approximately 1.8. Moreover, gene expression was markedly increased for all pancreatic genes, giving a approximately 50-fold elevation of insulin gene expression with respect to suspension culture. The distribution and presence of pancreatic hormones was also highly elevated. These findings provide a platform for the long-term maintenance and preservation of human pancreatic islets in vitro.


Assuntos
Ilhotas Pancreáticas/citologia , Alicerces Teciduais , Células Cultivadas , Matriz Extracelular/química , Imunofluorescência , Humanos , Ilhotas Pancreáticas/metabolismo , Reação em Cadeia da Polimerase Via Transcriptase Reversa
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