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BACKGROUND: Graft rejection and chronic CNI toxicity remain obstacles to organ transplant success. Current formulations of tacrolimus, such as Prograf® and Advagraf™, exhibit limitations in terms of pharmacokinetics and tolerability, related in part to suboptimal bioavailability. As dosing non-compliance can result in graft rejection, the once daily formulation of tacrolimus, Advagraf™, was developed (vs 2x/day Prograf®). Benefits of Advagraf™ are counterbalanced by delayed achievement of therapeutic trough levels and need for up to 50% higher doses to maintain Prograf®-equivalent troughs. Envarsus® is also a prolonged-release once-daily tacrolimus formulation, developed using MeltDose™ drug-delivery technology to increase drug bioavailability; improved bioavailability results in low patient drug absorption variability and less pronounced peak-to-trough fluctuations. In phase III de novo kidney transplant studies, Envarsus® proved non-inferior to twice-daily tacrolimus; however, no phase IV studies show superiority of Envarsus® vs Advagraf™ in de novo liver transplant (LTx) recipients. METHODS: The EnGraft compares bioavailability and tests superiority of Envarsus® (test arm) versus Advagraf™ (comparator arm) in de novo LTx recipients. A total of 268 patients from 15 German transplant centres will be randomised 1:1 within 14 days post-LTx. The primary endpoint is dose-normalised trough level (C/D ratio) measured 12 weeks after randomisation. Secondary endpoints include the number of dose adjustments, time to reach first defined trough level and incidence of graft rejections. Additionally, clinical and laboratory parameters will be assessed over a 3-year period. DISCUSSION: C/D ratio is an estimate for tacrolimus bioavailability. Improving bioavailability and increasing C/D ratio using Envarsus could reduce renal dysfunction and other tacrolimus-related toxicities; previous trials have shown that a higher C/D ratio (i.e. slower tacrolimus metabolism) is not only associated with improved renal function but also linked to reduced neurotoxic side effects. A higher C/D ratio could improve clinical outcomes for LTx recipients; EnGraft has begun, with one third of patients recruited by January 2022. TRIAL REGISTRATION: This trial has been registered (4 May 2020) in the EU Clinical Trials Register, EudraCT-Nummer: 2020-000796-20. Additionally, this trial has been registered (22 January 2021) at ClinicalTrials.gov: NCT04720326. The trial received a favourable opinion from the concerned lead ethics committee at the University of Regensburg, under the reference 20-1842-112.
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Trasplante de Riñón , Trasplante de Hígado , Humanos , Disponibilidad Biológica , Preparaciones de Acción Retardada , Rechazo de Injerto/prevención & control , Rechazo de Injerto/tratamiento farmacológico , Inmunosupresores , Trasplante de Riñón/efectos adversos , Trasplante de Hígado/efectos adversos , Estudios Multicéntricos como Asunto , Tacrolimus/efectos adversos , Ensayos Clínicos Controlados Aleatorios como AsuntoRESUMEN
BACKGROUND: Recipient selection for liver transplantation in hepatocellular carcinoma (HCC) is based primarily on criteria affecting the chance of long-term success. Here, the relationship between pretransplant bridging therapy and long-term survival was investigated in a subgroup analysis of the SiLVER Study. METHODS: Response to bridging, as defined by comparison of imaging at the time of listing and post-transplant pathology report, was categorized into controlled versus progressive disease (more than 20 per cent tumour growth or development of new lesions). RESULTS: Of 525 patients with HCC who had liver transplantation, 350 recipients underwent pretransplant bridging therapy. Tumour progression despite bridging was an independent risk factor affecting overall survival (hazard ratio 1.80; P = 0.005). For patients within the Milan criteria (MC) at listing, mean overall survival was longer for those with controlled versus progressive disease (6.8 versus 5.8 years; P < 0.001). Importantly, patients with HCCs outside the MC that were downsized to within the MC before liver transplantation had poor outcomes compared with patients who never exceeded the MC (mean overall survival 6.2 versus 6.6 years respectively; P = 0.030). CONCLUSION: Patients with HCCs within the MC that did not show tumour progression under locoregional therapy had the best outcomes after liver transplantation. Downstaging into the limits of the MC did not improve the probability of survival.Prognostic factors determining the long-term success of liver transplantation in patients with hepatocellular carcinoma are still under discussion. A subgroup analysis of the SiLVER trial showed that disease control under bridging therapy is strongly associated with improved prognosis in terms of overall survival. However, in tumours exceeding the limits of the Milan criteria, downstaging did not restore the probability of survival compared with that of patients within the Milan criteria.
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Carcinoma Hepatocelular/cirugía , Neoplasias Hepáticas/cirugía , Trasplante de Hígado/estadística & datos numéricos , Recurrencia Local de Neoplasia/prevención & control , Carcinoma Hepatocelular/mortalidad , Carcinoma Hepatocelular/patología , Progresión de la Enfermedad , Femenino , Humanos , Neoplasias Hepáticas/mortalidad , Neoplasias Hepáticas/patología , Masculino , Persona de Mediana Edad , Análisis Multivariante , Pronóstico , Factores de Riesgo , Análisis de Supervivencia , Factores de Tiempo , Resultado del Tratamiento , Listas de EsperaRESUMEN
BACKGROUND: In addition to a broad and clinically diverse spectrum of known primary cutaneous lymphomas, for which an incidence of 1-3:100,000 is postulated, each year further entities are specified and defined. The goal is the presentation of a case series from daily clinical routine. METHODS: Over a period of 6 years and 2 months, patients consulting the Department of Dermatology, Medical Center University of Freiburg, were registered. Subsequently, collectives of mycosis fungoides (MF), Sezary syndrome (SS), CD30+ lymphoproliferative diseases, single cases with rare primary cutaneous lymphomas, and subcollectives of Bcell lymphomas were examined. The high number of MF cases allowed the additional quantitative analyses of the types of therapies used in this group. RESULTS: Yearly 16-25 new diagnoses of primary cutaneous lymphoma are made. The evaluation of 163 primary cutaneous lymphoma revealed 111 cases with MF (68.1%), including 9 particular variants, 15 primary cutaneous CD30+ lymphoproliferative diseases (9.2%) dominated by 10 lymphomatoid papulosis (LyP), in addition to 5 primary cutaneous anaplastic large cell lymphoma (PCALCL), 6 SS (3.68%), and 24 cutaneous Bcell lymphomas (14-72%). Three cases with rare primary cutaneous T/NK cell lymphomas are addressed in detail. In all, 82% of MF cases were stage IA and IB. The descending use of therapies for stage I-III included steroids and diverse UV therapies followed by bexarotene, interferon-α, methotrexate, and extracorporal photophoresis. CONCLUSIONS: Diagnoses of cutaneous lymphomas belong to a vast spectrum of differential diagnoses. This registry describes frequent findings and shows rare variants. You can only diagnose what you know; accordingly, a collection of case reports, which we wish to encourage, can help in processing and specification of entities.
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Linfoma Cutáneo de Células T/clasificación , Linfoma Cutáneo de Células T/epidemiología , Papulosis Linfomatoide/epidemiología , Micosis Fungoide/epidemiología , Neoplasias Cutáneas/clasificación , Neoplasias Cutáneas/epidemiología , Alemania/epidemiología , Humanos , Antígeno Ki-1 , Papulosis Linfomatoide/patología , Micosis Fungoide/patologíaRESUMEN
Thermoresponsive hydrogels have enormous potential e.g., as sensors, actuators, and pollution control remedies or in drug delivery systems. Nevertheless, their application is often restricted by physical limitations (poor mechanical strength and uncontrolled thermal response). Composite systems may offer a means of overcoming these limitations. This paper presents a systematic study of the structure and dynamics of graphene oxide-poly-(N-isopropylacrylamide) composite systems, and investigates the effect of the nanoparticle filler content on the mechanical and swelling properties of the systems. A combination of macroscopic (swelling and elastic modulus) and microscopic (differential scanning microcalorimetry, small angle neutron scattering and neutron spin-echo spectroscopy) investigations reveals that the architecture of the polymer network is modified by chain nucleation at the surface of the GO platelets, and these form a percolating network inside the gel. Our results show that the elastic modulus of the gels is reinforced by the filler, but the mobility of the polymer chains in the swollen state is practically unaffected. The macroscopic deswelling of the composites, however, is slowed by the kinetics of ordering in the GO network.
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Fibrosis is a major component of chronic cardiac allograft rejection. Although several cell types are able to produce collagen, resident (donor-derived) fibroblasts are mainly responsible for excessive production of extracellular matrix proteins. It is currently unclear which cells regulate production of connective tissue elements in allograft fibrosis and how basophils, as potential producers of profibrotic cytokines, are involved this process. We studied this question in a fully MHC-mismatched model of heart transplantation with transient depletion of CD4(+) T cells to largely prevent acute rejection. The model is characterized by myocardial infiltration of leukocytes and development of interstitial fibrosis and allograft vasculopathy. Using depletion of basophils, IL-4-deficient recipients and IL-4 receptor-deficient grafts, we showed that basophils and IL-4 play crucial roles in activation of fibroblasts and development of fibrotic organ remodeling. In the absence of CD4(+) T cells, basophils are the predominant source of IL-4 in the graft and contribute to expansion of myofibroblasts, interstitial deposition of collagen and development of allograft vasculopathy. Our results indicated that basophils trigger the production of various connective tissue elements by myofibroblasts. Basophil-derived IL-4 may be an attractive target for treatment of chronic allograft rejection.
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Basófilos/inmunología , Rechazo de Injerto/etiología , Cardiopatías/etiología , Trasplante de Corazón/efectos adversos , Interleucina-4/fisiología , Aloinjertos , Animales , Femenino , Fibrosis/etiología , Fibrosis/patología , Rechazo de Injerto/patología , Supervivencia de Injerto , Cardiopatías/patología , Ratones , Ratones Endogámicos BALB C , Ratones Endogámicos C57BL , Ratones NoqueadosRESUMEN
Transplant recipients face an increased risk of cancer compared with the healthy population. Although several studies have examined the direct effects of immunosuppressive drugs on cancer cells, little is known about the interactions between pharmacological immunosuppression and cancer immunosurveillance. We investigated the different effects of rapamycin (Rapa) versus cyclosporine A (CsA) on tumor-reactive CD8(+) T cells. After adoptive transfer of CD8(+) T cell receptor-transgenic OTI T cells, recipient mice received either skin grafts expressing ovalbumin (OVA) or OVA-expressing B16F10 melanoma cells. Animals were treated daily with Rapa or CsA. Skin graft rejection and tumor growth as well as molecular and cellular analyses of skin- and tumor-infiltrating lymphocytes were performed. Both Rapa and CsA were equally efficient in prolonging skin graft survival when applied at clinically relevant doses. In contrast to Rapa-treated animals, CsA led to accelerated tumor growth in the presence of adoptively transferred tumor-reactive CD8(+) OTI T cells. Further analyses showed that T-bet was downregulated by CsA (but not Rapa) in CD8(+) T cells and that cancer cytotoxicity was profoundly inhibited in the absence of T-bet. CsA reduces T-bet-dependent cancer immunosurveillance by CD8(+) T cells. This may contribute to the increased cancer risk in transplant recipients receiving calcineurin inhibitors.
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Linfocitos T CD8-positivos/inmunología , Ciclosporina/farmacología , Rechazo de Injerto/inmunología , Tolerancia Inmunológica/inmunología , Melanoma Experimental/inmunología , Trasplante de Piel , Proteínas de Dominio T Box/fisiología , Animales , Femenino , Rechazo de Injerto/tratamiento farmacológico , Supervivencia de Injerto/efectos de los fármacos , Supervivencia de Injerto/inmunología , Tolerancia Inmunológica/efectos de los fármacos , Inmunosupresores/farmacología , Masculino , Melanoma Experimental/tratamiento farmacológico , Melanoma Experimental/patología , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Sirolimus/farmacologíaRESUMEN
Citrate is one of the major substrates for intracellular metabolism. The extracellular level of citrate is stable in blood but varies locally, with slightly increased levels in brain and high levels in prostate. Recent metabolomics research suggests that citrate level is a potential harbinger of different pathophysiological states; its decrease has been correlated with male infertility, brain diseases and metastatic cancer. In this review we discuss the role of citrate as an energy substrate for sperm. We also review the function of citrate released by astrocytes in the normal operation of neurons, and consequently we suggest a potential role of neuronal plasma membrane citrate transporters in mental disorders. Finally, we review recent relevant publications studying blood, urine and tissue citrate levels in cancer patients and hypothesize that extracellular citrate supports cancer cell metabolism critical for metastasis. Despite the importance of extracellular citrate in physiological and pathophysiological processes, surprisingly little is known about citrate synthesis in specialized cells, or about citrate transporters controlling citrate movement across various membranes. Determination of the molecular origin of citrate transporters in astrocytes, sperm and cancer cells could offer novel therapeutic targets and the possibility to pharmacologically regulate citrate release and uptake for preventing male infertility, treating mental diseases and targeting cancer.
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Trastorno Bipolar/metabolismo , Ácido Cítrico/metabolismo , Demencia/metabolismo , Espacio Extracelular/metabolismo , Infertilidad Masculina/metabolismo , Neoplasias de la Próstata/metabolismo , Astrocitos/metabolismo , Astrocitos/patología , Transporte Biológico , Trastorno Bipolar/patología , Trastorno Bipolar/fisiopatología , Encéfalo/metabolismo , Encéfalo/patología , Encéfalo/fisiopatología , Membrana Celular/metabolismo , Membrana Celular/patología , Demencia/patología , Demencia/fisiopatología , Células Epiteliales/metabolismo , Células Epiteliales/patología , Humanos , Infertilidad Masculina/patología , Infertilidad Masculina/fisiopatología , Masculino , Neuronas/metabolismo , Neuronas/patología , Especificidad de Órganos , Próstata/metabolismo , Próstata/patología , Próstata/fisiopatología , Neoplasias de la Próstata/patología , Neoplasias de la Próstata/fisiopatología , Espermatozoides/metabolismo , Espermatozoides/patologíaRESUMEN
BACKGROUND: Systemic therapy has proven only marginal effects in hepatocellular carcinoma (HCC) so far. The aim of this study was to evaluate the effect of targeting fibroblast growth factor receptor (FGFR) on tumour and stromal cells in HCC models. METHODS: Human and murine HCC cells, endothelial cells (ECs), vascular smooth muscle cells (VSMCs), hepatic stellate cells (HSCs), human HCC samples, FGFR inhibitor BGJ398 and mammalian target of rapamycin (mTOR) inhibitor rapamycin were used. Effects on growth, motility, signalling and angiogenic markers were determined. In vivo subcutaneous and syngeneic orthotopic tumour models were used. RESULTS: In tumour cells and ECs, targeting FGFR showed significant inhibitory effects on signalling and motility. Minor effects of FGFR inhibition were observed on VSMCs and HSCs, which were significantly enhanced by combining FGFR and mTOR blockade. In vivo daily (5 mg kg(-1)) treatment with BGJ398 led to a significant growth inhibition in subcutaneous tumour models, but only a combination of FGFR and mTOR blockade impaired tumour growth in the orthotopic model. This was paralleled by reduced tumour cell proliferation, vascularisation, pericytes and increased apoptosis. CONCLUSIONS: Targeting FGFR with BGJ398 affects tumour cells and ECs, whereas only a combination with mTOR inhibition impairs recruitment of VSMCs and HSCs. Therefore, this study provides evidence for combined FGFR/mTOR inhibition in HCC.
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Carcinoma Hepatocelular/tratamiento farmacológico , Neoplasias Hepáticas/tratamiento farmacológico , Compuestos de Fenilurea/farmacología , Pirimidinas/farmacología , Receptor Tipo 1 de Factor de Crecimiento de Fibroblastos/antagonistas & inhibidores , Sirolimus/farmacología , Serina-Treonina Quinasas TOR/antagonistas & inhibidores , Animales , Carcinoma Hepatocelular/patología , Línea Celular Tumoral , Movimiento Celular/efectos de los fármacos , Proliferación Celular/efectos de los fármacos , Sinergismo Farmacológico , Regulación Neoplásica de la Expresión Génica/efectos de los fármacos , Células Hep G2 , Humanos , Neoplasias Hepáticas/patología , Ratones , Ratones Desnudos , Trasplante de Neoplasias , Compuestos de Fenilurea/administración & dosificación , Pirimidinas/administración & dosificación , Transducción de Señal/efectos de los fármacos , Sirolimus/administración & dosificación , Ensayos Antitumor por Modelo de XenoinjertoRESUMEN
The innate receptor "triggering-receptor-expressed-on-myeloid-cells-1" (TREM-1) enhances downstream signaling of "pattern recognition receptor" (PRR) molecules implicated in inflammatory responses. However the mechanistic role of TREM-1 in chronic heart rejection has yet to be elucidated. We examined the effect of TREM-1(+) antigen-presenting cells (APC) on alloreactive CD4(+) lymphocytes. Bm12 donor hearts were transplanted into wild-type MHC-class-II-mismatched C57BL/6J recipient mice. Progressive allograft rejection of bm12-donor hearts with decreased organ function, severe vasculopathy and allograft fibrosis was evident within 4 weeks. TREM-1(+) CD11b(+) MHC-II(+) F4/80(+) CCR2(+) APC and IFNγ-producing CD4(+) cells were detected during chronic rejection. Peptide inhibition of TREM-1 attenuated graft vasculopathy, reduced graft-infiltrating leukocytes and prolonged allograft survival, while being accompanied by sustained low levels of CD4(+) and CD8(+) cell infiltration. Remarkably, temporary inhibition of TREM-1 during early immune activation was sufficient for long-term allograft survival. Mechanistically, TREM-1 inhibition leads to reduced differentiation and proliferation of IFNγ-producing Th1 cells. In conclusion, TREM-1 influences chronic heart rejection by regulating the infiltration and differentiation of CD4(+) lymphocytes.
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Linfocitos T CD4-Positivos/inmunología , Rechazo de Injerto/prevención & control , Supervivencia de Injerto/inmunología , Trasplante de Corazón/inmunología , Activación de Linfocitos/inmunología , Glicoproteínas de Membrana/antagonistas & inhibidores , Receptores Inmunológicos/antagonistas & inhibidores , Animales , Células Presentadoras de Antígenos/inmunología , Técnicas de Cocultivo , Modelos Animales de Enfermedad , Femenino , Citometría de Flujo , Regulación de la Expresión Génica , Rechazo de Injerto/genética , Rechazo de Injerto/inmunología , Supervivencia de Injerto/efectos de los fármacos , Supervivencia de Injerto/genética , Inmunohistoquímica , Glicoproteínas de Membrana/biosíntesis , Glicoproteínas de Membrana/genética , Ratones , Ratones Endogámicos C57BL , ARN/genética , Reacción en Cadena en Tiempo Real de la Polimerasa , Receptores Inmunológicos/biosíntesis , Receptores Inmunológicos/genética , Transducción de Señal/inmunología , Trasplante Homólogo , Receptor Activador Expresado en Células Mieloides 1RESUMEN
Mesenchymal stem cells (MSC) are under investigation as a therapy for a variety of disorders. Although animal models show long term regenerative and immunomodulatory effects of MSC, the fate of MSC after infusion remains to be elucidated. In the present study the localization and viability of MSC was examined by isolation and re-culture of intravenously infused MSC. C57BL/6 MSC (500,000) constitutively expressing DsRed-fluorescent protein and radioactively labeled with Cr-51 were infused via the tail vein in wild-type C57BL/6 mice. After 5 min, 1, 24, or 72 h, mice were sacrificed and blood, lungs, liver, spleen, kidneys, and bone marrow removed. One hour after MSC infusion the majority of Cr-51 was found in the lungs, whereas after 24 h Cr-51 was mainly found in the liver. Tissue cultures demonstrated that viable donor MSC were present in the lungs up to 24 h after infusion, after which they disappeared. No viable MSC were found in the other organs examined at any time. The induction of ischemia-reperfusion injury in the liver did not trigger the migration of viable MSC to the liver. These results demonstrate that MSC are short-lived after i.v. infusion and that viable MSC do not pass the lungs. Cell debris may be transported to the liver. Long term immunomodulatory and regenerative effects of infused MSC must therefore be mediated via other cell types.
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Immunosuppressive therapy required to treat rejection after lung transplantation (LTx) contributes significantly to the pathogenesis of cytomegalovirus (CMV) infection and disease. In a weak allogeneic left LTx model in the rat (Fisher 344 [F344] to Wistar Kyoto [WKY] rats) we analyzed the influence of acute CMV infection on postoperative day (POD) 3, with application of standard triple-drug immunosuppression (TD-IS) (cyclosporin A, azathioprine, prednisolone) on late outcome after LTx. Native right lungs and syngeneic grafts (WKY to WKY) served as controls. Rats were sacrificed on POD 15, 30, 60, and 100. TD-IS completely prevented acute and chronic rejection in non-infected rats. Allografts of CMV-infected rats treated with TD-IS showed only mild perivascular infiltrations in 6/10 rats (POD 15 and 30), which persisted up to POD 100 in 4/10 rats. In the long-term course, mild isolated interstitial and alveolar changes were found in 40% of these animals. In conclusion, rat CMV infection partially neutralized the immunosuppressive effect of TD-IS. However, an amplification of CMV infection under TD-IS can be controlled and does not result in fatal outcome.
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Infecciones por Citomegalovirus/etiología , Inmunosupresores/efectos adversos , Trasplante de Pulmón/efectos adversos , Animales , Azatioprina/administración & dosificación , Azatioprina/efectos adversos , Azatioprina/uso terapéutico , Ciclosporina/administración & dosificación , Ciclosporina/efectos adversos , Ciclosporina/uso terapéutico , Citomegalovirus/aislamiento & purificación , Infecciones por Citomegalovirus/virología , Regulación de la Expresión Génica/inmunología , Huésped Inmunocomprometido , Inmunosupresores/administración & dosificación , Inmunosupresores/uso terapéutico , Pulmón/virología , Prednisolona/administración & dosificación , Prednisolona/efectos adversos , Prednisolona/uso terapéutico , Ratas , Ratas Endogámicas F344 , Ratas Endogámicas WKY , Glándulas Salivales/virología , Timo/virología , Factores de Tiempo , Trasplante IsogénicoRESUMEN
Because of its antitumor effect, the immunosuppressant rapamycin holds great promise for organ transplant recipients in that it may lower their cancer risk. In a mouse model, we showed previously that rapamycin inhibits the outgrowth of primary skin carcinomas induced by UV radiation. However, the tumors that did grow out showed an altered p53 mutation spectrum. Here, we investigated whether this shift in p53 mutations already occurred in the smallest tumors, which were not affected in onset. We found that rapamycin did not alter the mutational spectrum in small tumors and in preceding microscopic clusters of cells expressing mutant-p53. However, rapamycin did reduce the number of these cell clusters. As this reduction did not affect tumor onset, we subsequently investigated whether rapamycin merely suppressed expression of mutated p53. This was not the case, as we could demonstrate that switching from a diet with rapamycin to one without, or vice versa, did not affect the number of existing mutant-p53 expressing cell clusters. Hence, rapamycin actually reduced the formation of mutant-p53 cell clusters. In wild-type and p53-mutant mice, we could not measure a significant enhancement of UV-induced apoptosis, but we did observe clear enhancement in human skin equivalents. This was associated with a clear suppression of HIF1α accumulation. Thus, we conclude that rapamycin reduces the formation of mutant-p53-expressing cell clusters without affecting tumor onset, suggesting that tumors grow out of a minor subset of cell clusters, the formation of which is not affected by rapamycin.
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Antibióticos Antineoplásicos/farmacología , Genes p53 , Mutación , Neoplasias Inducidas por Radiación/prevención & control , Sirolimus/farmacología , Animales , Apoptosis/efectos de los fármacos , Caspasa 3/análisis , Humanos , Subunidad alfa del Factor 1 Inducible por Hipoxia/antagonistas & inhibidores , Ratones , Ratones Pelados , Neoplasias Inducidas por Radiación/genética , Rayos UltravioletaRESUMEN
A 69-year-old patient presented with different skin lesions all of which belonged to group of necrobiosis lipoidica. The initial histologic diagnosis was actinic granuloma O'Brien. A subsequent biopsy was interpreted as granulomatous necrobiosis lipoidica. The history of these necrobiotic variants is reviewed and exemplarily depicted with this case. Necrobiosis lipoidica is part of the spectrum of granulomatous skin disorders. Although its etiology is unclear, an association with diabetes mellitus is often discussed. Multiple therapeutic options exist, but standardized guidelines for treatment are missing.
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Granuloma de Células Gigantes/diagnóstico , Queratosis Actínica/diagnóstico , Necrobiosis Lipoidea/diagnóstico , Anciano , Biopsia , Diagnóstico Diferencial , Femenino , Granuloma de Células Gigantes/patología , Humanos , Queratosis Actínica/patología , Necrobiosis Lipoidea/patología , Piel/patologíaRESUMEN
INTRODUCTION: Transplantation medicine offers multiple translational questions which should preferably be transferred to clinical evidence. The current gold standard for testing such questions and hypotheses is by prospective randomized controlled trials (RCT). The trials should be performed independently from the medical industry to avoid conflicts of interests and to guarantee a strict scientific approach. A good model is an investigator initiated trial (IIT) in which academic institutions function as the sponsor and in which normally a scientific idea stands before marketing interests of a certain medical product. METHODS: We present a model for an IIT which is sponsored and coordinated by Regensburg University Hospital at 45 sites in 13 nations (SiLVER study), highlight special pitfalls of this study and offer alternatives to this approach. RESULTS: Finances: financial support in clinical trials can be obtained from the medical industry. Alternatively in Germany the Federal Ministry of Education and Research (Bundesministerium für Bildung und Forschung) offers annual grants. The expansion of financial support through foundations is desirable. Infrastructure: sponsorship within the pharmaceutics act (Arzneimittelgesetz) demands excellent infrastructural conditions and a professional team to accomplish clinical, logistic, regulatory, legal and ethical challenges in a RCT. If a large trial has sufficient financial support certain tasks can be outsourced and delegated to contract research organizations, coordinating centers for clinical trials or partners in the medical industry. CONCLUSIONS: Clinical scientific advances to improve evidence are an enormous challenge when performed as an IIT. However, academic sponsors can perform (international) IITs when certain rules are followed and should be defined as the gold standard when scientific findings have to be established clinically.
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Ética en Investigación , Ensayos Clínicos Controlados Aleatorios como Asunto/ética , Ensayos Clínicos Controlados Aleatorios como Asunto/métodos , Investigadores/ética , Investigadores/organización & administración , Trasplante/ética , Trasplante/métodos , Conflicto de Intereses , Industria Farmacéutica/ética , Medicina Basada en la Evidencia/ética , Medicina Basada en la Evidencia/organización & administración , Financiación Gubernamental/ética , Financiación Gubernamental/organización & administración , Alemania , Hospitales Universitarios/ética , Hospitales Universitarios/organización & administración , Humanos , Mercadotecnía/ética , Mercadotecnía/organización & administración , Estudios Multicéntricos como Asunto/ética , Estudios Multicéntricos como Asunto/métodos , Servicios Externos/ética , Servicios Externos/organización & administración , Estudios Prospectivos , Apoyo a la Investigación como Asunto/ética , Apoyo a la Investigación como Asunto/organización & administración , Investigación Biomédica Traslacional/ética , Investigación Biomédica Traslacional/organización & administraciónRESUMEN
Donor-derived mesenchymal stem cells (MSC) can induce long-term acceptance in a rat heart transplantation model when injected prior to transplantation in combination with mycophenolate mofetil (MMF). In contrast, MSC alone cause accelerated graft rejection. To better understand these conflicting data we studied the effects of MSC and MMF on lymphocyte populations in heart allografts and secondary lymphatic organs. Allogeneic MSC injected prior to transplantation are immunogenic in this model because activated CD4+ and CD8+ cells emerged earlier in secondary lymphatic organs of MSC- and MSC/MMF-treated animals, compared to animals not treated with MSC. Consequently T cells infiltrated the grafts of MSC-only treated animals promptly causing accelerated graft rejection. However, few T cells or antigen-presenting cells (APC) infiltrated the grafts of animals treated with MSC and MMF. Consistent with this finding, intercellular adhesion molecule 1 (ICAM-1) and E-selectin was down-regulated exclusively in MSC/MMF-treated grafts, indicating that MSC together with MMF interfere with endothelial activation. Additionally, the presence of interferon-gamma (IFN-γ) enhanced MSC capabilities to suppress T cell proliferation in vitro. Interestingly, MMF did not influence serum IFN-γ levels in vivo. Together, our data indicate that MSC pre-activate T cells, but co-treatment with MMF eliminates these T cells, decreases intragraft APC and T cell trafficking by inhibiting endothelial activation, and allows IFN-γ stimulation of suppressive MSC.
Asunto(s)
Selectina E/metabolismo , Rechazo de Injerto/prevención & control , Trasplante de Corazón/inmunología , Molécula 1 de Adhesión Intercelular/metabolismo , Células Madre Mesenquimatosas , Ácido Micofenólico/análogos & derivados , Animales , Células Presentadoras de Antígenos/efectos de los fármacos , Células Presentadoras de Antígenos/inmunología , Linfocitos T CD4-Positivos/efectos de los fármacos , Linfocitos T CD4-Positivos/inmunología , Linfocitos T CD8-positivos/efectos de los fármacos , Linfocitos T CD8-positivos/inmunología , Selectina E/inmunología , Endotelio Linfático/efectos de los fármacos , Endotelio Linfático/metabolismo , Rechazo de Injerto/inmunología , Terapia de Inmunosupresión/métodos , Inmunosupresores/inmunología , Inmunosupresores/farmacología , Molécula 1 de Adhesión Intercelular/inmunología , Interferón gamma/sangre , Interferón gamma/inmunología , Activación de Linfocitos/efectos de los fármacos , Activación de Linfocitos/inmunología , Trasplante de Células Madre Mesenquimatosas , Células Madre Mesenquimatosas/inmunología , Ácido Micofenólico/inmunología , Ácido Micofenólico/farmacología , Ratas , Ratas Endogámicas ACI , Ratas Endogámicas LewRESUMEN
The risk of renal transplant recipients developing a malignancy is increasingly recognized as a major issue impacting long-term overall survival. As immunosuppression is thought to contribute to the development of cancer but is therapeutically required to protect against kidney rejection, reducing cancer in this setting is a challenging objective. An important question is whether there is a selective difference between pharmacological immunosuppressants regarding effects on malignancy. Both experimental and clinical studies thus far suggest that calcineurin inhibitors tend to promote tumor development; mycophenolic acid prodrugs such as mycophenolate mofetil have exhibited some capacity to inhibit tumors, but the concentrations needed for this effect are well above levels sustainable in transplant recipients. In contrast to these immunosuppressive substances, despite its potent immunosuppressive effects, rapamycin has demonstrated an impressive ability to inhibit de novo tumor development, as well as reduce tumor growth once cancer is already established. The antitumor effects of rapamycin are being studied extensively and appear to stem from the central role that the mammalian target of rapamycin molecule plays in basic cellular processes such as cell growth and proliferation, which are also essential for neoplasm development. Pilot trials and retrospective analyses of clinical data, especially using sirolimus, are highly suggestive that rapamycin can inhibit tumors in the clinical transplant setting. Prospective clinical trials are currently underway that will bring definitive answers as to whether rapamycin treatment can act simultaneously as an immunosuppressive and anticancer agent, with the aim of reducing the long-term problem of posttransplant malignancy.
Asunto(s)
Inmunosupresores/uso terapéutico , Trasplante de Riñón/efectos adversos , Neoplasias/prevención & control , Sirolimus/uso terapéutico , Animales , Quimioterapia Combinada , Humanos , Inmunosupresores/efectos adversos , Neoplasias/enzimología , Neoplasias/etiología , Neoplasias/patología , Medición de Riesgo , Factores de Riesgo , Serina-Treonina Quinasas TOR/antagonistas & inhibidores , Serina-Treonina Quinasas TOR/metabolismo , Resultado del TratamientoRESUMEN
The effect of the simultaneous presence of mono- and divalent cations on the thermodynamics of polyelectrolyte solutions is not fully understood. In physiological conditions, combinations of these ions affect structure formation in biopolymer systems. It is known that divalent counterions form a tight sheath around the polymer backbone, while monovalent ions are distributed in a diffuse cloud. Dynamic light scattering measurements of the collective diffusion coefficient D and the osmotic compressibility of semi-dilute hyaluronan solutions containing different ratios of sodium and calcium ions are compared with simple polyelectrolyte models. Scaling relationships are derived in terms of polymer concentration and ionic strength J of the added salt. Differences in the effects of sodium and calcium ions are expressed only through J.
RESUMEN
The adenomatous polyposis coli (APC) gene is mutated in familial adenomatous polyposis. Mice with a heterozygous APC(Min) mutation develop multiple intestinal neoplasia (Min) leading to premature death. Early in colorectal carcinogenesis, APC(Min/+) mice show enhanced Akt-mammalian target of rapamycin (mTOR) signaling, which is paralleled by upregulation of oncogenic K(+) channels. In this study, we tested the effect of mTOR inhibition with rapamycin on tumor formation in APC(Min/+) mice and evaluated ion channel regulation. We found that continuous long-term rapamycin treatment of APC(Min/+) mice dramatically inhibits intestinal neoplasia. Moreover, although untreated APC(Min/+) mice lose weight, experience intestinal bleeding and succumb to multiple neoplasia by 22.3+/-1.4 weeks of age, mice treated with rapamycin maintain stable weight and survive long term (39.6+/-3.4 weeks), with more than 30% surviving >1 year. Impressively, abnormalities in colonic electrolyte transport typical for APC(Min/+) mice are abolished, along with the suppression of epithelial Na(+) channel (ENaC) and oncogenic K(+) ion channels BK, Elk1 and Erg1, both functionally and at mRNA levels. These results show that continuous prophylaxis by rapamycin markedly inhibits the development of APC mutation-related polyposis, and suggest a novel contributing mechanism of action through the blockade of intestinal oncogenic ion channels.
Asunto(s)
Proteína de la Poliposis Adenomatosa del Colon/genética , Codón sin Sentido , Neoplasias Intestinales/prevención & control , Canales Iónicos/metabolismo , Sirolimus/farmacología , Animales , Inmunosupresores/farmacología , Mucosa Intestinal/metabolismo , Neoplasias Intestinales/genética , Neoplasias Intestinales/metabolismo , Pólipos Intestinales/genética , Pólipos Intestinales/metabolismo , Pólipos Intestinales/prevención & control , Intestinos/efectos de los fármacos , Intestinos/patología , Péptidos y Proteínas de Señalización Intracelular/antagonistas & inhibidores , Péptidos y Proteínas de Señalización Intracelular/metabolismo , Ratones , Proteínas Serina-Treonina Quinasas/antagonistas & inhibidores , Proteínas Serina-Treonina Quinasas/metabolismo , Serina-Treonina Quinasas TOR , Pérdida de Peso/efectos de los fármacosRESUMEN
Increased skin cancer risk in organ transplant recipients has been experimentally emulated with enhanced UV carcinogenesis from administering conventional immunosuppressants. However, newer generation immunosuppressive drugs, rapamycin (Rapa) and mycophenolate mofetil (MMF), have been shown to impair angiogenesis and outgrowth of tumor implants. To ascertain the overall effect on UV carcinogenesis, Rapa and MMF were admixed into the food pellets of hairless SKH1 mice receiving daily sub-sunburn UV dosages. With immunosuppressive blood levels neither of the drugs affected onset of tumors (<2 mm), but in contrast to MMF, Rapa significantly increased latency of large tumors (>or=4 mm, medians of 190 vs 125 days) and reduced their multiplicity (1.6 vs 4.5 tumors per mouse at 200 days). Interestingly, tumors (>2 mm) from the Rapa-fed group showed a reduction in UV-signature p53 mutations (39% vs 90%) in favor of mutations from putative base oxidation. This shift in mutation spectrum was not essentially linked to the reduction in large tumors because it was absent in large tumors similarly reduced in number when feeding Rapa in combination with MMF, possibly owing to an antioxidant effect of MMF. Significantly fewer tumor cells were Vegf-positive in the Rapa-fed groups, but a correspondingly reduced expression of Hif1alpha target genes (Vegf, Ldha, Glut1, Pdk1) that would indicate altered glucose metabolism with increased oxidative stress was not found. Remarkably, we observed no effect of the immunosuppressants on UV-induced tumor onset, and with impaired tumor outgrowth Rapa could therefore strongly reduce skin carcinoma morbidity and mortality rates in organ transplant recipients.