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1.
Bioeng Transl Med ; 9(1): e10615, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-38193111

RESUMO

Long-term patient and graft survival has been achieved in organ transplantation but at the expense of toxic side effects that are associated with long-term use of nonspecific immunosuppressive drugs. Discovering new regulators of dendritic cells is the key for development of an ideal treatment to prevent immune rejection. We hypothesized that knockdown of circMAP2K2 induces immunosuppressive DCs and that treatment with circMAP2K2 silenced-DCs can prevent alloimmune rejection. DCs were cultured and transfected with siRNA for circMAP2K2. circMAP2K2 levels were measured by qRT-PCR. DC's maturation and immune function were assessed by flow cytometry and mixed lymphocyte reactions. The function of circMAP2K2 was illustrated by a series of RIP and IP. The therapeutics of engineered DCs was tested in a mouse heart transplantation model. We found that circMAP2K2 was highly expressed in mature DCs. Knockdown of circMAP2K2 reduced expression of MHCII, CD40 and CD80, attenuated the ability of DCs to activate allogeneic naïve T cells, and enhanced CD4+CD25+FOXP3+ regulatory T cells (Treg). circMAP2K2-induced immunosuppressive DCs by interacting with SENP3. Treatment with circMAP2K2-knockdown DCs attenuated alloimmune rejection and prolonged allograft survival in a murine heart transplantation model. The immune suppression induced in vivo was donor-antigen specific. In conclusion, knockdown of circMAP2K2 can induce immunosuppressive DCs which are able to inhibit overactive immune response, highlighting a new promising therapeutic approach for immune disorder diseases.

3.
Cancer Immunol Immunother ; 72(12): 3875-3893, 2023 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-37831146

RESUMO

Colorectal cancer (CRC) is the second most common cause of cancer mortality, with mismatch repair proficient (pMMR) and/or microsatellite stable (MSS) CRC making up more than 80% of metastatic CRC. Programmed death-ligand 1 (PD-L1) and programmed death 1 (PD-1) immune checkpoint inhibitors (ICIs) are approved as monotherapy in many cancers including a subset of advanced or metastatic colorectal cancer (CRC) with deficiency in mismatch repair (dMMR) and/or high microsatellite instability (MSI-H). However, proficient mismatch repair and microsatellite stable (pMMR/MSS) cold CRCs have not shown clinical response to ICIs alone. To potentiate the anti-tumor response of PD-L1/PD-1 inhibitors in patients with MSS cold cancer, combination strategies currently being investigated include dual ICI, and PD-L1/PD-1 inhibitors in combination with chemotherapy, radiotherapy, vascular endothelial growth factor (VEGF) /VEGF receptor (VEGFR) inhibitors, mitogen-activated protein kinase (MEK) inhibitors, and signal transducer and activation of transcription 3 (STAT3) inhibitors. This paper will review the mechanisms of PD-1/PD-L1 ICI resistance in pMMR/MSS CRC and potential combination strategies to overcome this resistance, summarize the published clinical experience with different combination therapies, and make recommendations for future avenues of research.


Assuntos
Neoplasias do Colo , Neoplasias Colorretais , Neoplasias Retais , Humanos , Antígeno B7-H1 , Inibidores de Checkpoint Imunológico/farmacologia , Inibidores de Checkpoint Imunológico/uso terapêutico , Receptor de Morte Celular Programada 1 , Fator A de Crescimento do Endotélio Vascular , Neoplasias Colorretais/tratamento farmacológico , Neoplasias Colorretais/genética , Instabilidade de Microssatélites
4.
Liver Transpl ; 29(6): 618-625, 2023 06 01.
Artigo em Inglês | MEDLINE | ID: mdl-36896964

RESUMO

Medical assistance in dying (MAiD) has been a legally approved practice in Canada since 2016. Only recently have patients undergoing MAiD also been considered as donors for liver transplantation (LT). This study aimed to evaluate a case series of LT outcomes for recipients with MAiD donors and was paired with a systematic literature review of studies assessing the efficacy of MAiD-associated liver donation. A retrospective chart review of patients registered within the LT Registry at London Health Sciences Centre (LHSC) in London, Ontario, Canada, that had received MAiD donor LT was conducted to develop a case series. Descriptive statistics were produced based on available patient outcomes information. The systematic review included euthanasia due to MAiD being a term exclusive to Canada. Case series had a 100% 1-year graft survival rate, with 50% of patients experiencing early allograft dysfunction but having no significant clinical outcome. A single case of postoperative biliary complication was reported. Median warm ischemic time ranged from 7.8-13 minutes among case series and literature reviews. Utilization of donation after circulatory death allografts procured after MAiD appears to be promising. Mechanisms associated with potential impact in postoperative outcomes include relatively lower warm ischemic time relative to donation after circulatory death Maastricht III graft recipients.


Assuntos
Transplante de Fígado , Suicídio Assistido , Humanos , Transplante de Fígado/efeitos adversos , Estudos Retrospectivos , Doadores de Tecidos , Ontário
5.
HPB (Oxford) ; 24(1): 72-78, 2022 01.
Artigo em Inglês | MEDLINE | ID: mdl-34176743

RESUMO

BACKGROUND: Post-operative pancreatic fistula (POPF) is the most significant cause of morbidity following distal pancreatectomy. Hemopatch™ is a thin, bovine collagen-based hemostatic sealant. We hypothesized that application of Hemopatch™ to the pancreatic stump following distal pancreatectomy would decrease the incidence of clinically-significant POPF. METHODS: We conducted a prospective, single-arm, multicentre phase II study of application of Hemopatch™ to the pancreatic stump following distal pancreatectomy. The primary outcome was clinically-significant POPF within 90 days of surgery. A sample size of 52 patients was required to demonstrate a 50% relative reduction in Grade B/C POPF from a baseline incidence of 20%, with a type I error of 0.2 and power of 0.75. Secondary outcomes included incidence of POPF (all grades), 90-day mortality, 90-day morbidity, re-interventions, and length of stay. RESULTS: Adequate fixation Hemopatch™ to the pancreatic stump was successful in all cases. The rate of grade B/C POPF was 25% (95%CI: 14.0-39.0%). There was no significant difference in the incidence of grade B/C POPF compared to the historical baseline (p = 0.46). The 90-day incidence of Clavien-Dindo grade ≥3 complications was 26.9% (95%CI: 15.6-41.0%). CONCLUSION: The use of Hemopatch™ was not associated with a decreased incidence of clinically-significant POPF compared to historical rates. (NCT03410914).


Assuntos
Pancreatectomia , Fístula Pancreática , Animais , Bovinos , Humanos , Pâncreas , Pancreatectomia/efeitos adversos , Fístula Pancreática/epidemiologia , Fístula Pancreática/etiologia , Fístula Pancreática/prevenção & controle , Complicações Pós-Operatórias/epidemiologia , Complicações Pós-Operatórias/prevenção & controle , Estudos Prospectivos , Estudos Retrospectivos
6.
J Heart Lung Transplant ; 40(7): 584-594, 2021 07.
Artigo em Inglês | MEDLINE | ID: mdl-34052126

RESUMO

BACKGROUND: While heart transplantation is used as a standard treatment for heart failure, transplant rejection continues to pose a challenge. Recent evidence has shown that circular RNA (circRNA) is a new type of gene regulator in cell development. Our aim was to demonstrate that treatment with tolerogenic dendritic cells (Tol-DCs) generated by circular RNA FSCN1 (circFSCN1) silencing could prevent alloimmune rejection and prolong heart graft survival in heart transplantation. METHODS: Bone marrow-derived DCs were transfected with circFSCN1 siRNA in vitro. The circFSCN1 level was measured by qRT-PCR. DC maturation was determined by flow cytometry. Mixed lymphocyte reactions (MLRs) were conducted to assess the function of DCs to activate T cells and to generate regulatory T cells (Tregs). In situ RNA hybridization and fluorescent microscopy were performed to detect the distribution of circFSCN1 in DCs. A heterotopic allogeneic murine heart transplantation was conducted where recipients were pre-treated with donor derived circFSCN1-silenced Tol-DCs. Heartbeat was monitored to assess immune rejection. RESULTS: Exonic circFSCN1 was highly expressed in the cytoplasm of mature DCs. Knockdown of circFSCN1 using siRNA arrested DCs at an immature state, impaired DC's ability to activate T cells and enhanced Treg generation. Treatment with circFSCN1-silenced Tol-DCs prevented alloimmune rejection, prolonged allograft survival, reduced fibrosis, and induced Tregs in vivo. CONCLUSIONS: Knockdown of circFSCN1 induces Tol-DCs and treatment with these Tol-DCs prevents alloimmune rejection and prolongs allograft survival. This is a promising therapeutic target to combat transplant rejection in heart transplantation and increases our understanding of circRNA in the immune system.


Assuntos
Células Dendríticas/imunologia , Regulação da Expressão Gênica , Rejeição de Enxerto/prevenção & controle , Transplante de Coração/efeitos adversos , Tolerância Imunológica/genética , Proteínas dos Microfilamentos/genética , RNA Circular/genética , Receptores Odorantes/genética , Animais , Modelos Animais de Doenças , Rejeição de Enxerto/genética , Rejeição de Enxerto/imunologia , Sobrevivência de Enxerto , Ativação Linfocitária , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C57BL , Proteínas dos Microfilamentos/biossíntese , Receptores Odorantes/biossíntese , Linfócitos T Reguladores/imunologia , Transplante Homólogo
7.
Transplantation ; 105(2): 308-317, 2021 02 01.
Artigo em Inglês | MEDLINE | ID: mdl-32776778

RESUMO

BACKGROUND: Ischemia-reperfusion injury (IRI) is the major cause of primary graft dysfunction in organ transplantation. The mitogen-activated protein kinase/extracellular signal-regulated kinase (ERK) signaling pathway plays a crucial role in cell physiological and pathological processes including IRI. This study aims to investigate whether inhibition of ERK signaling with U0126 can prevent prolonged cold IRI in heart transplantation. METHODS: Rat cardiac cell line H9c2 cells were treated with U0126 before exposure to hypothermic hypoxia/reoxygenation (H/R) conditions. The effect of U0126 on H9c2 cells in response to H/R stress was determined by measuring cell death, reactive oxygen species production, mitochondrial membrane potential, and ERK signaling activation. Mouse syngeneic heterotopic heart transplantation was conducted, where a donor heart was preserved in the University of Wisconsin (UW) solution supplemented with U0126 for 24 hours at 4°C before transplantation. Heart graft function, histopathologic changes, apoptosis, and fibrosis were measured to assess IRI. RESULTS: Phosphorylated ERK was increased in both in vitro H/R-injured H9c2 cells and in vivo heart grafts with IRI. Pretreatment with U0126 inhibited ERK phosphorylation and prevented H9c2 cells from cell death, reactive oxygen species generation, and mitochondrial membrane potential loss in response to H/R. Preservation of donor hearts with U0126-supplemented solution improved graft function and reduced IRI by reductions in cell apoptosis/death, neutrophil infiltration, and fibrosis of the graft. CONCLUSIONS: Addition of U0126 to UW solution reduces ERK signal activation and attenuates prolonged cold IRI in a heart transplantation model. ERK inhibition with U0126 may be a useful strategy to minimize IRI in organ transplantation.


Assuntos
Butadienos/farmacologia , Isquemia Fria , MAP Quinases Reguladas por Sinal Extracelular/antagonistas & inibidores , Transplante de Coração/efeitos adversos , Traumatismo por Reperfusão Miocárdica/prevenção & controle , Miócitos Cardíacos/efeitos dos fármacos , Nitrilas/farmacologia , Soluções para Preservação de Órgãos/farmacologia , Preservação de Órgãos , Inibidores de Proteínas Quinases/farmacologia , Adenosina/farmacologia , Alopurinol/farmacologia , Animais , Apoptose/efeitos dos fármacos , Hipóxia Celular , Linhagem Celular , Isquemia Fria/efeitos adversos , MAP Quinases Reguladas por Sinal Extracelular/metabolismo , Fibrose , Glutationa/farmacologia , Insulina/farmacologia , Masculino , Potencial da Membrana Mitocondrial/efeitos dos fármacos , Camundongos Endogâmicos C57BL , Traumatismo por Reperfusão Miocárdica/enzimologia , Traumatismo por Reperfusão Miocárdica/patologia , Traumatismo por Reperfusão Miocárdica/fisiopatologia , Miócitos Cardíacos/enzimologia , Miócitos Cardíacos/patologia , Preservação de Órgãos/efeitos adversos , Estresse Oxidativo/efeitos dos fármacos , Fosforilação , Rafinose/farmacologia , Ratos , Transdução de Sinais , Função Ventricular Esquerda/efeitos dos fármacos
8.
Cardiovasc Intervent Radiol ; 44(1): 163-166, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-32914368

RESUMO

We present the case of a 73-year-old female who underwent percutaneous cryoablation for recurrent life-threatening pancreatic vasoactive intestinal polypeptide-producing tumor (VIPoma) following a pancreaticoduodenectomy and chemotherapy 5 years earlier. She presented with profuse watery diarrhea causing severe electrolyte and acid-base abnormalities, along with acute kidney injury. Cryoablation was successful in treating her profound symptoms, completely reversing her clinical course. The patient has made a successful recovery for the last 1.5 years since the procedure.


Assuntos
Criocirurgia/métodos , Pancreatectomia/métodos , Neoplasias Pancreáticas/cirurgia , Vipoma/cirurgia , Idoso , Feminino , Humanos , Neoplasias Pancreáticas/diagnóstico , Síndrome , Tomografia Computadorizada por Raios X , Vipoma/diagnóstico
9.
Am J Transplant ; 21(9): 2992-3004, 2021 09.
Artigo em Inglês | MEDLINE | ID: mdl-33382168

RESUMO

Ischemia-reperfusion (I/R) injury occurring in heart transplantation (HT) remains as a leading cause of transplant heart graft failure. Circular RNAs (circRNAs) play important roles in gene regulation and diseases. However, the impact of circRNAs on I/R injury during HT remains unknown. This study aims to investigate the role of circular RNA Foxo3 (circFoxo3) in I/R injury in HT. Using an in vivo mouse HT model and an in vitro cardiomyocyte culture model, we demonstrated that circFoxo3 is significantly upregulated in I/R-injured hearts and hypoxia/reoxygenation (H/R)-damaged cardiomyocytes. Knockdown of circFoxo3 using siRNA not only reduces cell apoptosis and death, mitochondrial damage, and expression of apoptosis/death-related genes in vitro, but also protects heart grafts from prolonged cold I/R injury in HT. We also show that circFoxo3 interacts with Foxo3 proteins and inhibits the phosphorylation of Foxo3 and that it indirectly affects the expression of miR-433 and miR-136. In conclusion, circRNA is involved in I/R injury in HT and knockdown of circFoxo3 with siRNA can reduce I/R injury and improve heart graft function through interaction with Foxo3. This study highlights that circRNA is a new type of molecular regulator and a potential target for preventing I/R injury in HT.


Assuntos
Transplante de Coração , RNA Circular , Traumatismo por Reperfusão , Animais , Apoptose , Transplante de Coração/efeitos adversos , Camundongos , MicroRNAs/genética , Miócitos Cardíacos
10.
Inflamm Bowel Dis ; 26(6): 949-959, 2020 05 12.
Artigo em Inglês | MEDLINE | ID: mdl-31665288

RESUMO

BACKGROUND: Patients with inflammatory bowel disease (IBD) post-liver transplant (LT) may have bowel inflammation requiring biologic therapy. We aimed to evaluate the safety of combination biologic and antirejection therapy in IBD patients after LT from a tertiary center case series and an updated literature review. METHODS: Inflammatory bowel disease patients undergoing LT between 1985 and 2018 and requiring combination biologic and antirejection therapy post-LT were identified from the London Health Sciences Transplant Registry (Ontario, Canada). Safety outcomes were extracted by medical chart review. For an updated literature review, EMBASE, Medline, and CENTRAL were searched to identify studies evaluating the safety of combination biologic and antirejection therapy in IBD patients. RESULTS: In the case series, 19 patients were identified. Most underwent LT for primary sclerosing cholangitis (PSC; 14/19, 74%) treated with anti-integrins (8/19, 42%) or tumor necrosis factor α (TNF) antagonists (6/19, 32%). Infections occurred in 11/19 (58%) patients, most commonly Clostridium difficile (4/19, 21%). Two patients required colectomy, and 1 patient required re-transplantation. In the literature review, 13 case series and 8 case reports reporting outcomes for 122 IBD patients treated with biologic and antirejection therapy post-LT were included. PSC was the indication for LT in 97/122 (80%) patients, and 91/122 (75%) patients were treated with TNF antagonists. Infections occurred in 32/122 (26%) patients, primarily Clostridium difficile (7/122, 6%). CONCLUSIONS: Inflammatory bowel disease patients receiving combination biologic and antirejection therapy post-LT appeared to be at increased risk of Clostridium difficile. Compared with the general liver transplant population in the published literature, there was no increased risk of serious infection.


Assuntos
Produtos Biológicos/efeitos adversos , Infecções por Clostridium/etiologia , Terapia de Imunossupressão/efeitos adversos , Doenças Inflamatórias Intestinais/tratamento farmacológico , Transplante de Fígado , Adulto , Idoso , Produtos Biológicos/uso terapêutico , Colangite Esclerosante/complicações , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Ontário , Sistema de Registros , Fatores de Risco
11.
Can J Surg ; 62(1): 44-51, 2019 02 01.
Artigo em Inglês | MEDLINE | ID: mdl-30484989

RESUMO

Background: Outcomes in liver transplantation with organs obtained via donation after cardiocirculatory death (DCD) have been suboptimal compared to donation after brain death, attributed mainly to the high incidence of ischemic cholangiopathy (IC). We evaluated the effect of a 10-year learning curve on IC rates among DCD liver graft recipients at a single centre. Methods: We analyzed all DCD liver transplantation procedures from July 2006 to July 2016. Patients were grouped into early (July 2006 to June 2011) and late (July 2011 to July 2016) eras. Those with less than 6 months of follow-up were excluded. Primary outcomes were IC incidence and IC-free survival rate. Results: Among the 73 DCD liver transplantation procedures performed, 70 recipients fulfilled the selection criteria, 32 in the early era and 38 in the late era. Biliary complications were diagnosed in 19 recipients (27%). Ischemic cholangiopathy was observed in 8 patients (25%) in the early era and 1 patient (3%) in the late era (p = 0.005). The IC-free survival rate was higher in the late era than the early era (98% v. 79%, p = 0.01). The warm ischemia time (27 v. 24 min, p = 0.049) and functional warm ischemia time (21 v. 17 min, p = 0.002) were significantly lower in the late era than the early era. Conclusion: We found a significant reduction in IC rates and improvement in ICfree survival among DCD liver transplantation recipients after a learning curve period that was marked by more judicious donor selection with shorter procurement times.


Contexte: L'issue des greffes de foie suite à un don d'organe après décès cardiocirculatoire (DDC) a été sous-optimale comparativement aux dons suivant la mort cérébrale. Cela serait surtout attribuable à une forte incidence de cholangiopathie ischémique (CI). Nous avons évalué l'effet d'une courbe d'apprentissage échelonnée sur 10 ans sur les taux de CI chez des receveurs de greffe de foie après DDC dans un seul centre. Méthodes: Nous avons analysé toutes les greffes de foie consécutives à des DDC entre juillet 2006 et juillet 2016. Les patients ont été regroupés en 2 époques, la première, de juillet 2006 à juin 2011, et la seconde, de juillet 2011 à juillet 2016. Ceux pour lesquels on disposait de moins de 6 mois de suivi ont été exclus. Les paramètres principaux étaient l'incidence de CI et le taux de survie sans CI. Résultats: Parmi les 73 greffes de foie par suite de DDC, 70 receveurs répondaient aux critères de sélection, 32 pour la première époque et 38 pour la seconde époque. Des complications biliaires ont été diagnostiquées chez 19 receveurs (27 %). La cholangiopathie ischémique a été observée chez 8 patients (25 %) de la première époque et 1 patient (3 %) de la seconde (p = 0,005). Le taux de survie sans CI a été plus élevé pendant la seconde époque que pendant la première (98 % c. 79 %, p = 0,01). Le temps d'ischémie chaude (27 minutes c. 24, p = 0,049) et le temps d'ischémie chaude fonctionnelle (21 minutes c. 17, p = 0,002) ont été significativement plus courts durant la seconde époque que durant la première. Conclusion: Nous avons observé une réduction significative des taux de CI et une amélioration de la survie sans CI chez les receveurs de greffes de foie par DDC après une courbe d'apprentissage qui a été marquée par une sélection plus judicieuse des donneurs et des délais d'obtention plus courts.


Assuntos
Doenças dos Ductos Biliares/prevenção & controle , Morte , Doença Hepática Terminal/cirurgia , Isquemia/prevenção & controle , Transplante de Fígado/efeitos adversos , Isquemia Quente/normas , Adulto , Idoso , Doenças dos Ductos Biliares/etiologia , Canadá , Bases de Dados Factuais , Feminino , Sobrevivência de Enxerto , Humanos , Isquemia/etiologia , Masculino , Pessoa de Meia-Idade , Seleção de Pacientes , Estudos Retrospectivos , Análise de Sobrevida , Fatores de Tempo , Doadores de Tecidos , Coleta de Tecidos e Órgãos/normas , Obtenção de Tecidos e Órgãos/normas , Transplantados , Resultado do Tratamento
12.
A A Case Rep ; 9(4): 123-126, 2017 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-28459725

RESUMO

Spinal epidural hematoma (SEH) following neuraxial anesthesia needs prompt recognition and early decompressive measures to prevent long-term neurologic injury. We report a case of SEH presenting on the second postoperative day during an ongoing epidural infusion. Aspiration of blood through the epidural catheter and a subsequent improvement in the neurological symptoms made us suspect SEH, which was further confirmed by an MRI study. We describe the timeline of the presentation of SEH and the subsequent clinical course in our patient. Aspiration of blood through an in situ epidural catheter may not only point toward the possibility of SEH but may also temporarily decompress the spinal canal.


Assuntos
Anestesia Epidural/efeitos adversos , Descompressão Cirúrgica/métodos , Hematoma Epidural Espinal/etiologia , Espaço Epidural , Feminino , Hematoma Epidural Espinal/diagnóstico por imagem , Hematoma Epidural Espinal/cirurgia , Humanos , Imageamento por Ressonância Magnética , Pessoa de Meia-Idade
13.
Oncotarget ; 8(22): 36531-36544, 2017 May 30.
Artigo em Inglês | MEDLINE | ID: mdl-28388574

RESUMO

Ischemia reperfusion (I/R) injury which inevitably occurs during heart transplantation is the major factor leading to organ failure and graft rejection. In order to develop new therapies to prevent I/R injury, we used both a murine heart transplantation model with 24 hour cold I/R and an in vitro cell culture system to determine whether growth differentiation factor 15 (GDF15) is a protective factor in preventing I/R injury in heart transplantation and to further investigate underlying mechanisms of I/R injury. We found that cold I/R caused severe damage to the endocardium, epicardium and myocardium of heart grafts from wild type C57BL/6 mice, whereas grafts from GDF15 transgenic (TG) mice showed less damage as demonstrated by decreased cell apoptosis/death, decreased neutrophils infiltration and the preservation of the normal structure of the heart. Over-expression of GDF15 reduced expression of phosphorylated RelA p65, pre-inflammatory and pro-apoptotic genes while it enhanced Foxo3a phosphorylation in vitro and in vivo. Over-expression of GDF15 inhibited cell apoptosis/death and reduced neutrophil infiltration. In conclusion, this study, for the first time, demonstrates that GDF15 is a promising target for preventing cold I/R injury in heart transplantation. This study also shows that the resultant protective effects are mediated by the Foxo3 and NFκB signaling pathways.


Assuntos
Isquemia Fria/efeitos adversos , Proteína Forkhead Box O3/metabolismo , Expressão Gênica , Fator 15 de Diferenciação de Crescimento/genética , Transplante de Coração , Traumatismo por Reperfusão/etiologia , Traumatismo por Reperfusão/metabolismo , Animais , Apoptose/genética , Citocinas/genética , Citocinas/metabolismo , Humanos , Mediadores da Inflamação/metabolismo , Masculino , Camundongos , Miócitos Cardíacos/metabolismo , Peroxidase/metabolismo , Fosforilação , Ratos , Traumatismo por Reperfusão/prevenção & controle , Transdução de Sinais
14.
Sci Rep ; 6: 33869, 2016 Sep 23.
Artigo em Inglês | MEDLINE | ID: mdl-27659428

RESUMO

Toll-like receptors (TLRs) act as initiators and conductors responsible for both innate and adaptive immune responses in organ transplantation. The mammalian target of rapamycin (mTOR) is one of the most critical signaling kinases that affects broad aspects of cellular functions including metabolism, growth, and survival. Recipients (BALB/c) were treated with MyD88, TRIF and mTOR siRNA vectors, 3 and 7 days prior to heart transplantation and 7, 14 and 21 days after transplantation. After siRNA treatment, recipients received a fully MHC-mismatched C57BL/6 heart. Treatment with mTOR siRNA significantly prolonged allograft survival in heart transplantation. Moreover, the combination of mTOR siRNA with MyD88 and TRIF siRNA further extended the allograft survival; Flow cytometric analysis showed an upregulation of FoxP3 expression in spleen lymphocytes and a concurrent downregulation of CD40, CD86 expression, upregulation of PD-L1 expression in splenic dendritic cells in MyD88, TRIF and mTOR treated mice. There is significantly upregulated T cell exhaustion in T cells isolated from tolerant recipients. This study is the first demonstration of preventing immune rejection of allogeneic heart grafts through concurrent gene silencing of TLR and kinase signaling pathways, highlighting the therapeutic potential of siRNA in clinical transplantation.

16.
World J Hepatol ; 6(6): 443-7, 2014 Jun 27.
Artigo em Inglês | MEDLINE | ID: mdl-25018855

RESUMO

AIM: To determine if there is a reasonable prospect of success of a re-use liver transplantation. METHODS: We systematically searched for reports of liver graft re-use using electronic searches of PubMed and Web of Knowledge. We performed hand searches of references lists of articles reporting re-use of grafts. RESULTS: A systematic review of the literature reveals 28 liver transplantations using previously transplanted grafts. First and second recipients ranged in age from 4 to 72 years and 29 to 62 years respectively. Liver disease in the first recipient was varied including 5 (18%) patients with fulminant liver failure who died subsequently of cerebral edema. The second transplantation was performed after a median interval of 5 d (one day-13 years). Viral hepatitis was present in 3 (11%) of the initial recipients and in 8 (29%) of final recipients. Hepatocellular carcinoma was present in 6 (21%) of the final recipients. Early survival after the final transplantation was 93%, whereas long-term survival was 78% with a mean follow-up of 23.3 (3-120) mo. CONCLUSION: Outcomes of transplantation using previously transplanted grafts in this select population are similar to those seen with conventional grafts.

17.
J Transl Med ; 12: 142, 2014 May 22.
Artigo em Inglês | MEDLINE | ID: mdl-24886282

RESUMO

BACKGROUND: While substantial progress has been made in blocking acute transplant rejection with the advent of immune suppressive drugs, chronic rejection, mediated primarily by recipient antigen presentation, remains a formidable problem in clinical transplantation. We hypothesized that blocking co-stimulatory pathways in the recipient by induction of RNA interference using small interference RNA (siRNA) expression vectors can prolong allogeneic heart graft survival. METHOD: Vectors expressing siRNA specifically targeting CD40 and CD80 were prepared. Recipients (BALB/c mice) were treated with CD40 and/or CD80 siRNA expression vectors via hydrodynamic injection. Control groups were injected with a scrambled siRNA vector and sham treatment (PBS). After treatment, a fully MHC-mismatched (BALB/c to C57/BL6) heart transplantation was performed. RESULT: Allogeneic heart graft survival (>100 days) was approximately 70% in the mice treated simultaneously with CD40 and CD80 siRNA expression vectors with overall reduction in lymphocyte interstitium infiltration, vascular obstruction, and edema. Hearts transplanted into CD40 or CD80 siRNA vector-treated recipients had an increased graft survival time compared to negative control groups, but did not survive longer than 40 days. In contrast, allogenic hearts transplanted into recipients treated with scrambled siRNA vector and PBS stopped beating within 10-16 days. Real-time PCR (RT-PCR) and flow cytometric analysis showed an upregulation of FoxP3 expression in spleen lymphocytes and a concurrent downregulation of CD40 and CD80 expression in splenic dendritic cells of siRNA-treated mice. Functional suppressive activity of splenic dendritic cells (DCs) isolated from tolerant recipients was demonstrated in a mixed lymphocyte reaction (MLR). Furthermore, DCs isolated from CD40- and CD80-treated recipients promoted CD4+CD25+FoxP3+ regulatory T cell differentiation in vitro. CONCLUSION: This study demonstrates that the simultaneous silencing of CD40 and CD80 genes has synergistic effects in preventing allograft rejection, and may therefore have therapeutic potential in clinical transplantation.


Assuntos
Antígeno B7-1/genética , Antígenos CD40/genética , Inativação Gênica , Rejeição de Enxerto/prevenção & controle , Transplante de Coração , Animais , Sequência de Bases , Primers do DNA , Citometria de Fluxo , Rejeição de Enxerto/genética , Teste de Cultura Mista de Linfócitos , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C57BL , RNA Interferente Pequeno/genética , Reação em Cadeia da Polimerase em Tempo Real
18.
JAMA ; 311(18): 1863-9, 2014 May 14.
Artigo em Inglês | MEDLINE | ID: mdl-24825641

RESUMO

IMPORTANCE: Patients with colorectal cancer with liver metastases undergo hepatic resection with curative intent. Positron emission tomography combined with computed tomography (PET-CT) could help avoid noncurative surgery by identifying patients with occult metastases. OBJECTIVES: To determine the effect of preoperative PET-CT vs no PET-CT (control) on the surgical management of patients with resectable metastases and to investigate the effect of PET-CT on survival and the association between the standardized uptake value (ratio of tissue radioactivity to injected radioactivity adjusted by weight) and survival. DESIGN, SETTING, AND PARTICIPANTS: A randomized trial of patients older than 18 years with colorectal cancer treated by surgery, with resectable metastases based on CT scans of the chest, abdomen, and pelvis within the previous 30 days, and with a clear colonoscopy within the previous 18 months was conducted between 2005 and 2013, involving 21 surgeons at 9 hospitals in Ontario, Canada, with PET-CT scanners at 5 academic institutions. INTERVENTIONS: Patients were randomized using a 2 to 1 ratio to PET-CT or control. MAIN OUTCOMES AND MEASURES: The primary outcome was a change in surgical management defined as canceled hepatic surgery, more extensive hepatic surgery, or additional organ surgery based on the PET-CT. Survival was a secondary outcome. RESULTS: Of the 263 patients who underwent PET-CT, 21 had a change in surgical management (8.0%; 95% CI, 5.0%-11.9%). Specifically, 7 patients (2.7%) did not undergo laparotomy, 4 (1.5%) had more extensive hepatic surgery, 9 (3.4%) had additional organ surgery (8 of whom had hepatic resection), and the abdominal cavity was opened in 1 patient but hepatic surgery was not performed and the cavity was closed. Liver resection was performed in 91% of patients in the PET-CT group and 92% of the control group. After a median follow-up of 36 months, the estimated mortality rate was 11.13 (95% CI, 8.95-13.68) events/1000 person-months for the PET-CT group and 12.71 (95% CI, 9.40-16.80) events/1000 person-months for the control group. Survival did not differ between the 2 groups (hazard ratio, 0.86 [95% CI, 0.60-1.21]; P = .38). The standardized uptake value was associated with survival (hazard ratio, 1.11 [90% CI, 1.07-1.15] per unit increase; P < .001). The C statistic for the model including the standardized uptake value was 0.62 (95% CI, 0.56-0.68) and without it was 0.50 (95% CI, 0.44-0.56). The difference in C statistics is 0.12 (95% CI, 0.04-0.21). The low C statistic suggests that the standard uptake value is not a strong predictor of overall survival. CONCLUSIONS AND RELEVANCE: Among patients with potentially resectable hepatic metastases of colorectal adenocarcinoma, the use of PET-CT compared with CT alone did not result in frequent change in surgical management. These findings raise questions about the value of PET-CT scans in this setting. TRIAL REGISTRATION: clinicaltrials.gov Identifier: NCT00265356.


Assuntos
Adenocarcinoma/diagnóstico por imagem , Adenocarcinoma/cirurgia , Neoplasias Colorretais/patologia , Neoplasias Hepáticas/diagnóstico por imagem , Neoplasias Hepáticas/cirurgia , Tomografia por Emissão de Pósitrons , Adenocarcinoma/secundário , Adulto , Idoso , Idoso de 80 Anos ou mais , Feminino , Hepatectomia/métodos , Humanos , Neoplasias Hepáticas/secundário , Masculino , Pessoa de Meia-Idade , Cuidados Pré-Operatórios , Análise de Sobrevida , Tomografia Computadorizada por Raios X , Resultado do Tratamento , Adulto Jovem
19.
J Surg Res ; 185(2): 877-82, 2013 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-23953787

RESUMO

BACKGROUND: As the survival of patients after liver transplantation (LT) improves, the requirement of liver retransplantation (reLT) for late graft failure has grown. Although some have reported that the short-term outcome of late reLT was comparable with that of early reLT, it remains unknown whether long-term survival of late reLT is inferior to that of early reLT patients. MATERIALS AND METHODS: We reviewed early (<6 mo after primary LT) and late (≥6 mo after primary LT) reLT cases performed between January 2000 and December 2010. RESULTS: Sixteen early and 32 late reLT cases were analyzed. There was no significant difference regarding the number of units of red blood cells transfused during the transplantation between the groups, whereas operative time was significantly longer in the late reLT cases. Graft loss within 3 mo after early and late reLT was 18.6% and 15.6%, respectively. Patient and graft survival rates after 1, 3, 5, and 10 y in the late reLT group were 80.6%, 73.3%, 73.3%, and 67.7% and 80.7%, 69.1%, 63.3%, and 54.3%, respectively, whereas those in the early reLT group were 75.0%, 75.0%, 64.3%, and 64.3% and 81.3%, 75.0%, 64.3%, and 32.1%, respectively. There was no significant difference in patient or graft survival rates between the groups (P = 0.91 and 0.91, respectively). CONCLUSIONS: Acceptable short- and long-term survival were provided in early and late reLT. The time between the primary LT and reLT does not seem to play significant role in the prognosis of reLT in the long term.


Assuntos
Função Retardada do Enxerto/mortalidade , Sobrevivência de Enxerto , Hepatopatias/mortalidade , Transplante de Fígado/mortalidade , Complicações Pós-Operatórias/mortalidade , Reoperação/mortalidade , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Doença Crônica , Função Retardada do Enxerto/cirurgia , Feminino , Humanos , Hepatopatias/cirurgia , Masculino , Pessoa de Meia-Idade , Complicações Pós-Operatórias/cirurgia , Estudos Retrospectivos , Fatores de Tempo , Doadores de Tecidos , Adulto Jovem
20.
Hepatol Int ; 7(2): 728-33, 2013 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-26201807

RESUMO

PURPOSE: Although three or more liver transplantation (LT)s in the same patient arouse not only medical but also ethical issues in the context of organ shortage, it is a fact that additional liver retransplantation (reLT) is the only lifesaving treatment option for those with graft failure after a second LT. However, little is known regarding the risks and benefits associated with a third LT. METHODS: We analyzed fifteen cases of third LT and 48 of second LT performed between January 2000 and December 2010. Clinical outcomes were compared with those of second LT cases performed during the same period. RESULTS: Model for end-stage liver disease (MELD) scores at transplant was similar between the two groups. As for surgical aspects, there was no significant difference in operative time or number of units of red blood cells transfused during the transplant procedures between the groups. Patient and graft survival after the third LT at 1, 3, and 10 years were 66.7, 51.9, and 44.4 %, and 66.7, 51.9, and 29.6 %, respectively. There was no significant difference in patient or graft survival between the groups. However, graft loss within 3 months after the third LT was significantly higher than that of second LT patients. CONCLUSION: Third LT cases showed acceptable short- and long-term outcomes that were not significantly inferior to those of a second LT. Careful patient care especially in the early phase after a third LT may be essential to improve the outcome.

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