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Transplantation of stem/progenitor cells holds promise for cardiac regeneration in patients with myocardial infarction (MI). Currently, however, low cell survival and engraftment after transplantation present a major barrier to many forms of cell therapy. One issue is that ligands, receptors, and signaling pathways that promote graft success remain poorly understood. Here, we prospectively isolate uncommitted epicardial cells from the adult heart surface by CD104 (ß-4 integrin) and demonstrate that C-terminal peptide from connective tissue growth factor (CTGF-D4), when combined with insulin, effectively primes epicardial-derived cells (EPDC) for cardiac engraftment after MI. Similar to native epicardial derivatives that arise from epicardial EMT at the heart surface, the grafted cells migrated into injured myocardial tissue in a rat model of MI with reperfusion. By echocardiography, at 1 month after MI, we observed significant improvement in cardiac function for animals that received epicardial cells primed with CTGF-D4/insulin compared with those that received vehicle-primed (control) cells. In the presence of insulin, CTGF-D4 treatment significantly increased the phosphorylation of Wnt co-receptor LRP6 on EPDC. Competitive engraftment assays and neutralizing/blocking studies showed that LRP6 was required for EPDC engraftment after transplantation. Our results identify LRP6 as a key target for increasing EPDC engraftment after MI and suggest amplification of LRP6 signaling with CTGF-D4/insulin, or by other means, may provide an effective approach for achieving successful cellular grafts in regenerative medicine.
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Factor de Crecimiento del Tejido Conjuntivo/metabolismo , Insulinas , Infarto del Miocardio , Animales , Corazón , Humanos , Proteína-6 Relacionada a Receptor de Lipoproteína de Baja Densidad/metabolismo , Infarto del Miocardio/metabolismo , Infarto del Miocardio/terapia , Miocardio/metabolismo , RatasRESUMEN
Objectives: End-stage kidney disease (ESKD) is a life-limiting illness that leads to significant health-related suffering for the patients and their caregivers. Moreover, disease-directed options such as dialysis and renal transplant might not be universally accessible. Inadequate assessment and management of symptoms often lead to diminished quality of life. For evaluating symptoms and their associated distress, various tools have been identified. However, these are not available for the native Kannada-speaking population for assessing ESKD symptom burden. In this study, we determined the reliability and validity of the Edmonton Symptom Assessment System Revised Renal (ESAS-r: Renal) in Kannada-speaking ESKD patients. Materials and Methods: ESAS-r: Renal English version was translated into Kannada using the forward and backward method. The translated version was endorsed by Nephrology, Palliative care, Dialysis technology and Nursing experts. As a pilot study, 12 ESKD patients evaluated the content of the questionnaires for appropriateness and relevance. The ESAS-r: Renal Kannada version was validated by administering this tool to 45 patients twice a fortnight. Result: The translated ESAS-r: Renal Kannada version questionnaire had an acceptable face and content validity. Experts' opinion was assessed by content validity ratio (CVR), and the value of CVR of ESAS-r: Renal Kannada version was-'1'-. Internal consistency of the tool was assessed among Kannada-speaking ESKD patients; its Cronbach's α was 0.785, and test-retest validity was 0.896. Conclusion: The validated Kannada version of ESAS-r: Renal was reliable and valid for assessing symptom burden in ESKD patients.
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Objectives: Palliative care (PC) referral in serious and critical COVID-19 improves decision-making, health resource utilisation, end-of-life symptom management and family support. In this study, we explored developing a systematic decision-making matrix for PC referral in COVID-19 and audited its outcomes. Materials and Methods: A team of interdisciplinary experts developed a hospital COVID-19 PC plan. PC referral and outcomes of PC referral in hospitalised COVID-19 patients were audited. Results: Out of 1575 inpatients, 1066 (67.7%) had mild and 509 (32.3%) had serious and critical COVID-19 illness. Among 50 (3.1%) referred to PC, 5 (0.4%) had mild and 45 (8.8%) had serious and critical COVID-19 illness. Out of 45 serious and critical COVID-19 patients referred to PC, 38 (84%) received end-of-life care (EOLC), 4 (9%) self-discharged against medical advice and 3 (7%) recovered. Forty-seven (94%) were referred for goals-of-care discussion. About 78% received opioids, 70% benzodiazepines and 42% haloperidol for symptom management. Among 45 serious and critical COVID-19 patients referred to PC, foregoing life-sustaining treatment was documented in 43 (96%) but implemented only in 23 (53%). Out of 38 who received EOLC, ICU was the place of death in 31 (82%) and ward in 7 (18%). Conclusion: Despite interdisciplinary experts developing a hospital COVID-19 PC, low referral of serious and critical COVID-19 patients to PC was observed. PC referral enabled access to management of end-of-life symptoms and facilitated limitation of life-sustaining treatment in some COVID-19 patients with serious illness. Educating critical care physicians about the scope of PC in the COVID-19 setting might improve PC referral.
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Zebrafish regenerate cardiac tissue through proliferation of pre-existing cardiomyocytes and neovascularization. Secreted growth factors such as FGFs, IGF, PDGFs and Neuregulin play essential roles in stimulating cardiomyocyte proliferation. These factors activate the Ras/MAPK pathway, which is tightly controlled by the feedback attenuator Dual specificity phosphatase 6 (Dusp6), an ERK phosphatase. Here, we show that suppressing Dusp6 function enhances cardiac regeneration. Inactivation of Dusp6 by small molecules or by gene inactivation increased cardiomyocyte proliferation, coronary angiogenesis, and reduced fibrosis after ventricular resection. Inhibition of Erbb or PDGF receptor signaling suppressed cardiac regeneration in wild-type zebrafish, but had a milder effect on regeneration in dusp6 mutants. Moreover, in rat primary cardiomyocytes, NRG1-stimulated proliferation can be enhanced upon chemical inhibition of Dusp6 with BCI. Our results suggest that Dusp6 attenuates Ras/MAPK signaling during regeneration and that suppressing Dusp6 can enhance cardiac repair.
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Fosfatasa 6 de Especificidad Dual/fisiología , Corazón/fisiología , Sistema de Señalización de MAP Quinasas/fisiología , Proteínas Proto-Oncogénicas p21(ras)/metabolismo , Regeneración/genética , Pez Cebra/fisiología , Animales , Animales Modificados Genéticamente , Proliferación Celular/genética , Regulación hacia Abajo/genética , Miocitos Cardíacos/fisiología , Transducción de Señal/genética , Proteínas de Pez Cebra/fisiologíaRESUMEN
Rationale: The role of FSTL-1 (follistatin-like 1) in lung homeostasis is unknown.Objectives: We aimed to define the impact of FSTL-1 attenuation on lung structure and function and to identify FSTL-1-regulated transcriptional pathways in the lung. Further, we aimed to analyze the association of FSTL-1 SNPs with lung disease.Methods: FSTL-1 hypomorphic (FSTL-1 Hypo) mice underwent lung morphometry, pulmonary function testing, and micro-computed tomography. Fstl1 expression was determined in wild-type lung cell populations from three independent research groups. RNA sequencing of wild-type and FSTL-1 Hypo mice identified FSTL-1-regulated gene expression, followed by validation and mechanistic in vitro examination. FSTL1 SNP analysis was performed in the COPDGene (Genetic Epidemiology of Chronic Obstructive Pulmonary Disease) cohort.Measurements and Main Results: FSTL-1 Hypo mice developed spontaneous emphysema, independent of smoke exposure. Fstl1 is highly expressed in the lung by mesenchymal and endothelial cells but not immune cells. RNA sequencing of whole lung identified 33 FSTL-1-regulated genes, including Nr4a1, an orphan nuclear hormone receptor that negatively regulates NF-κB (nuclear factor-κB) signaling. In vitro, recombinant FSTL-1 treatment of macrophages attenuated NF-κB p65 phosphorylation in an Nr4a1-dependent manner. Within the COPDGene cohort, several SNPs in the FSTL1 region corresponded to chronic obstructive pulmonary disease and lung function.Conclusions: This work identifies a novel role for FSTL-1 protecting against emphysema development independent of smoke exposure. This FSTL-1-deficient emphysema implicates regulation of immune tolerance in lung macrophages through Nr4a1. Further study of the mechanisms involving FSTL-1 in lung homeostasis, immune regulation, and NF-κB signaling may provide additional insight into the pathophysiology of emphysema and inflammatory lung diseases.
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Proteínas Relacionadas con la Folistatina/genética , Pulmón/diagnóstico por imagen , Enfisema Pulmonar/genética , Humo/efectos adversos , Animales , Células Endoteliales/metabolismo , Proteínas Relacionadas con la Folistatina/farmacología , Regulación de la Expresión Génica , Técnicas de Silenciamiento del Gen , Humanos , Técnicas In Vitro , Pulmón/metabolismo , Macrófagos/efectos de los fármacos , Macrófagos/metabolismo , Ratones , Mutación , Miembro 1 del Grupo A de la Subfamilia 4 de Receptores Nucleares/efectos de los fármacos , Miembro 1 del Grupo A de la Subfamilia 4 de Receptores Nucleares/metabolismo , Fosforilación/efectos de los fármacos , Polimorfismo de Nucleótido Simple , Tomografía Computarizada por Tomografía de Emisión de Positrones , Enfermedad Pulmonar Obstructiva Crónica/genética , Enfisema Pulmonar/diagnóstico por imagen , Enfisema Pulmonar/metabolismo , Tomografía Computarizada por Tomografía Computarizada de Emisión de Fotón Único , Nicotiana , Factor de Transcripción ReIA/efectos de los fármacos , Factor de Transcripción ReIA/metabolismo , Microtomografía por Rayos XRESUMEN
Maggots are dipterous larvae of flies. Infestation of vertebrate animals (including humans) by maggots is termed as Myiasis. Warm and Humid climate, low socio-economic status, lack of knowledge and poor living conditions, malignant wounds predispose the cancer patients to maggot infestation in India. Apart from infestation in the wounds; oral, ophthalmic, nasal, aural, enteric, urogenital, trachea-pulmonary and rectal myiasis have been reported. Maggot infestation of the Intercostal drain (ICD) container without associated pleural myiasis is an extremely rare entity. We describe a rare case report of maggots in the ICD in a patient with metastatic chondrosarcoma femur with ICD in situ for malignant pleural effusion. Early detection and management are the keys to prevent the catastrophic complication of pleural myiasis.
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The decision regarding dialysis initiation is complex. Awareness that renal replacement therapy should not be regarded as default therapy for every patient with advanced renal failure is necessary. Decision to initiate dialysis and modality should be individualized in a shared decision-making process involving the treating nephrologist and the patient. Patients should receive predialysis education early in the course of chronic kidney disease so as to help prepare them well in advance for this eventuality. Withholding dialysis may be a reasonable option in a certain subset of patients, especially elderly patient with multiple co-morbid illnesses. Comprehensive conservation care should be offered in all patients where the decision to not dialyze is taken.
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OBJECTIVES: Early integrated palliative care has shown to improve the quality of life in patients with cancer. During the past decade, pediatric palliative care has become an established area of medical expertise, however due to scant information available regarding the triggers for referral and referral practice very few children receive a formal palliative care consult. MATERIALS AND METHODS: A retrospective audit of medical case records of pediatric oncology patients over a period of 1 year from September 30, 2019, to September 30, 2020, was conducted. Demographic details, diagnosis, staging, clinical parameters, reason for referral, and palliative care plan were captured in a predesigned pro forma. RESULTS: Among 126 children with cancer, 27 (21.4%) patients were referred to palliative care. Majority 21 (77%) referrals were inpatient consults. Symptom management 17 (44.7%) was the most common trigger for referral followed by referrals for psychosocial support 12 (14.4%). Children with solid tumors 16 (59%) were more often referred than hematological malignancies. Among those needing end of life care, 8 (88.8%) out of 9 families preferred home than hospital. CONCLUSION: Low incidence of palliative care referral and presence of symptoms as a trigger for palliative care referral suggests gaps in the integrated approach. The study findings prompt a review of palliative care referral criteria and referral practice in a pediatric oncology setting.
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Transplantation of culture-expanded adult stem/progenitor cells often results in poor cellular engraftment, survival, and migration into sites of tissue injury. Mesenchymal cells including fibroblasts and stromal cells secrete factors that protect injured tissues, promote tissue repair, and support many types of stem/progenitor cells in culture. We hypothesized that secreted factors in conditioned medium (CdM) from adult bone marrow-derived multipotent stromal cells (MSCs) could be used to prime adult cardiac stem/progenitor cells (CSCs/CPCs) and improve graft success after myocardial infarction (MI). Incubation of adult rat CPCs in CdM from human MSCs isolated by plastic adherence or by magnetic sorting against CD271 (a.k.a., p75 low-affinity nerve growth factor receptor; p75MSCs) induced phosphorylation of STAT3 and Akt in CPCs, supporting their proliferation under normoxic conditions and survival under hypoxic conditions (1% oxygen). Priming CSCs with 30× p75MSC CdM for 30 minutes prior to transplantation into subepicardial tissue 1 day after MI markedly increased engraftment compared with vehicle priming. Screening CdM with neutralizing/blocking antibodies identified connective tissue growth factor (CTGF) and Insulin as key factors in p75MSC CdM that protected CPCs. Human CTGF peptide (CTGF-D4) and Insulin synergistically promoted CPC survival during hypoxia in culture. Similar to CdM priming, priming of CSCs with CTGF-D4 and Insulin for 30 minutes prior to transplantation promoted robust engraftment, survival, and migration of CSC derivatives at 1 week and 1 month after MI. Our results indicate that short-term priming of human CSCs with CTGF-D4 and Insulin may improve graft success and cardiac regeneration in patients with MI.
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Infarto del Miocardio/terapia , Miocardio/patología , Trasplante de Células Madre , Células Madre/citología , Células Madre/metabolismo , Adulto , Animales , Bovinos , Diferenciación Celular/efectos de los fármacos , Hipoxia de la Célula/efectos de los fármacos , Línea Celular , Proliferación Celular/efectos de los fármacos , Factor de Crecimiento del Tejido Conjuntivo/metabolismo , Medios de Cultivo Condicionados/farmacología , Activación Enzimática/efectos de los fármacos , Humanos , Infusiones Intraarteriales , Insulina/metabolismo , Ligandos , Células Madre Multipotentes/citología , Infarto del Miocardio/patología , Sustancias Protectoras/metabolismo , Proteínas Proto-Oncogénicas c-akt/metabolismo , Ratas , Factor de Transcripción STAT3/metabolismo , Células Madre/efectos de los fármacos , Células Madre/enzimología , Células del Estroma/citología , Células del Estroma/efectos de los fármacosRESUMEN
Ischemic stroke-induced mitochondrial dysfunction in the blood-brain barrier-forming brain endothelial cells (BECs) results in long-term neurological dysfunction post-stroke. We previously reported data from a pilot study where intravenous administration of human BEC (hBEC)-derived mitochondria-containing extracellular vesicles (EVs) showed a potential efficacy signal in a mouse middle cerebral artery occlusion (MCAo) model of stroke. We hypothesized that EVs harvested from donor species homologous to the recipient species (e.g., mouse) may improve therapeutic efficacy, and therefore, use of mouse BEC (mBEC)-derived EVs may improve post-stroke outcomes in MCAo mice. We investigated potential differences in the mitochondria transfer of EVs derived from the same species as the recipient cell (mBEC-EVs and recipient mBECs or hBECs-EVs and recipient hBECs) vs. cross-species EVs and recipient cells (mBEC-EVs and recipient hBECs or vice versa). Our results showed that while both hBEC- and mBEC-EVs transferred EV mitochondria, mBEC-EVs outperformed hBEC-EVs in increasing ATP levels and improved recipient mBEC mitochondrial function via increasing oxygen consumption rates. mBEC-EVs significantly reduced brain infarct volume and neurological deficit scores compared to vehicle-injected MCAo mice. The superior therapeutic efficacy of mBEC-EVs in MCAo mice support the continued use of mBEC-EVs to optimize the therapeutic potential of mitochondria-containing EVs in preclinical mouse models.
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Ischemic stroke-induced mitochondrial dysfunction in the blood-brain barrier-forming brain endothelial cells ( BECs ) results in long-term neurological dysfunction post-stroke. We previously data from a pilot study where intravenous administration of human BEC ( hBEC )-derived mitochondria-containing extracellular vesicles ( EVs ) showed a potential efficacy signal in a mouse middle cerebral artery occlusion ( MCAo ) model of stroke. We hypothesized that EVs harvested from donor species homologous to the recipient species ( e.g., mouse) may improve therapeutic efficacy, and therefore, use of mouse BEC ( mBEC )-derived EVs may improve post-stroke outcomes in MCAo mice. We investigated potential differences in the mitochondria transfer of EVs derived from the same species as the recipient cell (mBEC-EVs and recipient mBECs or hBECs-EVs and recipient hBECs) vs . cross-species EVs and recipient cells (mBEC-EVs and recipient hBECs or vice versa ). Our results showed that while both hBEC- and mBEC-EVs transferred EV mitochondria, mBEC-EVs outperformed hBEC-EVs in increasing ATP levels and improved recipient mBEC mitochondrial function via increasing oxygen consumption rates. mBEC-EVs significantly reduced brain infarct volume and neurological deficit scores compared to vehicle-injected MCAo mice. The superior therapeutic efficacy of mBEC-EVs in a mouse MCAo stroke support the continued use of mBEC-EVs to optimize the therapeutic potential of mitochondria-containing EVs in preclinical mouse models.
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Dicarboxylic fatty acids are generated in the liver and kidney in a minor pathway called fatty acid ω-oxidation. The effects of consuming dicarboxylic fatty acids as an alternative source of dietary fat have not been explored. Here, we fed dodecanedioic acid, a 12-carbon dicarboxylic (DC12), to mice at 20% of daily caloric intake for nine weeks. DC12 increased metabolic rate, reduced body fat, reduced liver fat, and improved glucose tolerance. We observed DC12-specific breakdown products in liver, kidney, muscle, heart, and brain, indicating that oral DC12 escaped first-pass liver metabolism and was utilized by many tissues. In tissues expressing the "a" isoform of acyl-CoA oxidase-1 (ACOX1), a key peroxisomal fatty acid oxidation enzyme, DC12 was chain shortened to the TCA cycle intermediate succinyl-CoA. In tissues with low peroxisomal fatty acid oxidation capacity, DC12 was oxidized by mitochondria. In vitro, DC12 was catabolized even by adipose tissue and was not stored intracellularly. We conclude that DC12 and other dicarboxylic acids may be useful for combatting obesity and for treating metabolic disorders.
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Hepatocyte Growth Factor (HGF) and Fibroblast Growth Factor 2 (FGF2) are receptor tyrosine kinase agonists that promote cell survival after tissue injury and angiogenesis, cell proliferation and migration during tissue repair and regeneration. Both ligands have potential as systemic treatments for ischemia-reperfusion injury, however clinical use of HGF and FGF2 has been limited by poor pharmacokinetic profiles, i.e., their susceptibility to serum proteases, rapid clearance and short half-lives. Previously, we reported vaso- and cardioprotective protein complexes formed between HGF and polyclonal, non-specific immunoglobulin (IgG) with therapeutic efficacy in a rat model of myocardial ischemia with reperfusion (MI/R). Here, using a pre-clinical porcine MI/R model, we demonstrate human HGF/IgG complexes provide significant myocardial salvage, reduce infarct size, and are detectable in myocardial tissue 24 h after intracoronary injection. Furthermore, we show that multiple daily infusions of HGF/IgG complexes after MI do not lead to production of HGF-specific auto-antibodies, an important concern for administered biologic drugs. In experiments to identify other growth factors that non-covalently interact with IgG, we found that human FGF2 associates with IgG. Similar to human HGF/IgG complexes, FGF2/IgG complexes protected primary human cardiac endothelial cells under simulated ischemia (1% oxygen and nutrient deprivation) for 48-72 h. Molecular modeling studies suggested that FGF2 and HGF both interact with the Fc domain of IgG. Also, we tested whether an Fc-fusion protein would bind FGF2 to form complexes. By native gel electrophoretic assays and biochemical pulldowns, we found that Jagged1, a Notch1 ligand that controls stem cell self-renewal and tissue regeneration, bound FGF2 when presented as a Jagged1- Fc fusion protein. Our results suggest that human growth factor/IgG and FGF2/Fc- fusion complexes have potential to provide a biologics platform to treat myocardial ischemia-reperfusion and other forms of tissue injury.
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Hypoplastic left heart syndrome (HLHS) is a severe congenital heart disease with 30% mortality from heart failure (HF) in the first year of life, but the cause of early HF remains unknown. Induced pluripotent stem-cell-derived cardiomyocytes (iPSC-CM) from patients with HLHS showed that early HF is associated with increased apoptosis, mitochondrial respiration defects, and redox stress from abnormal mitochondrial permeability transition pore (mPTP) opening and failed antioxidant response. In contrast, iPSC-CM from patients without early HF showed normal respiration with elevated antioxidant response. Single-cell transcriptomics confirmed that early HF is associated with mitochondrial dysfunction accompanied with endoplasmic reticulum (ER) stress. These findings indicate that uncompensated oxidative stress underlies early HF in HLHS. Importantly, mitochondrial respiration defects, oxidative stress, and apoptosis were rescued by treatment with sildenafil to inhibit mPTP opening or TUDCA to suppress ER stress. Together these findings point to the potential use of patient iPSC-CM for modeling clinical heart failure and the development of therapeutics.
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Cardiopatías Congénitas , Insuficiencia Cardíaca , Células Madre Pluripotentes Inducidas , Antioxidantes/metabolismo , Cardiopatías Congénitas/metabolismo , Insuficiencia Cardíaca/metabolismo , Humanos , Poro de Transición de la Permeabilidad Mitocondrial , Miocitos Cardíacos/metabolismo , Estrés OxidativoRESUMEN
PURPOSE OF REVIEW: Ischemic heart disease and stroke lead to the greatest number of deaths worldwide. Despite decreased time to intervention and improvements in the standard of care, 1 out of 5 patients that survive a myocardial infarction (MI) still face long-term chronic heart failure and a 5-year mortality rate of about 50%. Based on their multi-potency for differentiation and paracrine activity, epicardial cells and their derivatives have potential to rescue jeopardized tissue and/or promote cardiac regeneration. Here we review the diagnosis and treatment of MI, basic epicardial cell biology, and potential treatment strategies designed to harness the reparative properties of epicardial cells. RECENT FINDINGS: During cardiac development, epicardial cells covering the surface of the heart generate migratory progenitor cells that contribute to the coronary vasculature and the interstitial fibroblasts. Epicardial cells also produce paracrine signals required for myocardial expansion and cardiac growth. In adults with myocardial infarction, epicardial cells and their derivatives provide paracrine factors that affect myocardial remodeling and repair. At present, the intrinsic mechanisms and extrinsic signals that regulate epicardial cell fate and paracrine activity in adults remain poorly understood. SUMMARY: Human diseases that result in heart failure due to negative remodeling or extensive loss of viable cardiac tissue require new, effective treatments. Improved understanding of epicardial cell function(s) and epicardial-mediated secretion of growth factors, cytokines and hormones during cardiac growth, homeostasis and injury may lead to new ways to treat patients with myocardial infarction.
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AIMS: The aim of this study was to evaluate the paracrine activity of human epicardial-derived cells (hEPDCs) to screen for secreted vasoprotective factors and develop therapeutics to treat vascular reperfusion injury. METHODS AND RESULTS: Epicardial cells support cardiac development, repair, and remodelling after injury in part, through paracrine activity. We hypothesized that secreted ligands from hEPDCs would protect vascular integrity after myocardial infarction (MI) with reperfusion. During simulated ischaemia in culture (24-48 h), concentrated hEPDC-conditioned medium (EPI CdM) increased survival of primary cardiac endothelial cells. In a rat MI model, EPI CdM treatment reduced vascular injury in vivo after reperfusion. By phospho-receptor tyrosine kinase (RTK) arrays, ELISA, and neutralizing antibody screens, we identified hepatocyte growth factor (HGF) as a key vasoprotective factor in EPI CdM. Unexpectedly, we observed that some of the HGF in EPI CdM formed complexes with polyclonal IgG. Following reperfusion, preparations of HGF/IgG complexes provided greater vascular protection than free HGF with IgG. HGF/IgG complexes localized to blood vessels in vivo and increased HGF retention time after administration. In subsequent screens, we found that 'related to tyrosine kinase' (RYK) receptor was phosphorylated after exposure of cardiac endothelial cells to HGF/IgG complexes, but not to free HGF with IgG. The enhanced protection conferred by HGF/IgG complexes was lost after antibody blockade of RYK. Notably, the HGF/IgG complex is the first 'ligand' shown to promote phosphorylation of RYK. CONCLUSION: Early treatment with HGF/IgG complexes after myocardial ischaemia with reperfusion may rescue tissue through vasoprotection conferred by c-Met and RYK signalling.
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Factor de Crecimiento de Hepatocito/metabolismo , Infarto del Miocardio/metabolismo , Proteínas Tirosina Quinasas Receptoras/metabolismo , Lesiones del Sistema Vascular/metabolismo , Animales , Factor de Crecimiento de Hepatocito/inmunología , Humanos , Inmunoglobulina G/inmunología , Masculino , Isquemia Miocárdica/metabolismo , Ratas Endogámicas F344RESUMEN
The intracellular delivery of growth factors increases opportunities for controlling cell behavior and maintaining tissue homeostasis. Recently, VEGFA was reported to enhance osteogenic differentiation of mesenchymal stem cells (MSCs) through an intracrine mechanism, suggesting a new strategy to promote bone tissue formation in osteoporotic patients. The goal of this study was to design and fabricate ligand-conjugated alginate-graft-poly(ethylene glycol) microspheres for intracellular delivery and release of VEGFA in primary human MSCs to enhance osteogenic differentiation as a potential therapeutic. Three types of microspheres were synthesized and characterized by scanning electron microscopy, in vitro drug release kinetics, MSC uptake and internalization: alginate alone (Alg), alginate-graft-poly(ethylene glycol) (Alg-g-PEG) and alginate-graft-poly(ethylene glycol)-S-S-arginine-glycine-aspartic acid (Alg-g-RGD). Each of the different microsphere formulations successfully transported bioactive VEGFA into primary human MSCs within 48h of culture, and significantly enhanced osteogenic differentiation compared to control treatments with empty microspheres (intracellular control) or non-encapsulated VEGFA (extracellular control). Adipogenic differentiation was not affected by the presence of VEGFA intracellularly or extracellularly. These results demonstrating the internalization of alginate-based microspheres and intracellular delivery of VEGFA support the efficacy of using this drug delivery and intracrine mechanism to control the fate of human MSCs and enhance osteogenic differentiation.