RESUMO
Previous work by our group has shown the pro-differentiating effects of apotransferrin (aTf) on oligodendroglial cells in vivo and in vitro. Further studies showed the remyelinating effect of aTf in animal demyelination models such as hypoxia/ischemia, where the intranasal administration of human aTf provided brain neuroprotection and reduced white matter damage, neuronal loss, and astrogliosis in different brain regions. These data led us to search for a less invasive and controlled technique to deliver aTf to the CNS. To such end, we isolated extracellular vesicles (EVs) from human and mouse plasma and different neuron and glia conditioned media and characterized them based on their quality, quantity, identity, and structural integrity by western blot, dynamic light scattering, and scanning electron microscopy. All sources yielded highly pure vesicles whose size and structures were in keeping with previous literary evidence. Given that, remarkably, EVs from all sources analyzed contained Tf receptor 1 (TfR1) in their composition, we employed two passive cargo-loading strategies which rendered successful EV loading with aTf, specifically through binding to TfR1. These results unveil EVs as potential nanovehicles of aTf to be delivered into the CNS parenchyma, and pave the way for further studies into their possible clinical application in the treatment of demyelinating diseases.
Assuntos
Apoproteínas/metabolismo , Vesículas Extracelulares/metabolismo , Nanopartículas/metabolismo , Receptores da Transferrina/metabolismo , Transferrina/metabolismo , Adulto , Animais , Apoproteínas/administração & dosagem , Astrócitos/efeitos dos fármacos , Astrócitos/metabolismo , Linhagem Celular Transformada , Linhagem Celular Tumoral , Células Cultivadas , Feminino , Humanos , Masculino , Camundongos , Nanopartículas/administração & dosagem , Ratos , Ratos Wistar , Receptores da Transferrina/administração & dosagem , Transferrina/administração & dosagemRESUMO
Lactoferrin (LF), an iron-binding protein with antioxidant activity, is significantly reduced in the lacrimal film of patients affected by keratoconus (KC) compared to healthy subjects, and this is supposed to be the cause for tear iron increase and consequent iron deposition and oxygen free radical accumulation in the cornea. We decided to study if LF-loaded contact lenses (LF-CLs) could exert antioxidant activity on epithelial cells incubated in tears collected from two patients affected by keratoconus (KC1 and KC2). Moreover through this model we indirectly estimated iron concentration in the tears of healthy and KC subjects. Reflex tears were collected during the first 2 min of light or onion-induced lacrimation and stored at -20 °C. After incubation in tears for 18 h, mortality of epithelial cells was investigated by trypan blue exclusion test. Successively, LF-CLs were deposed on cells incubated in KC1 tears. For the indirect determination of iron content, cells were incubated with LF 1.2 mg/mL and different FeSO4 concentrations, and for the estimation of iron from the patient's tears, cells were incubated with free serum medium and healthy tears (1:1) and different FeSO4 concentrations. Epithelial cells incubated with reflex tears of KC patients showed increased mortality (27.7 ± 3.9%, p = 0.0003, for KC1 and 17.6 ± 0.95%, p = 0.014, for KC2) compared to epithelial cells maintained in control healthy tears (8.6 ± 1.2%). This difference in mortality was correlated with tear iron concentration, which was estimated at 4.58 µg/mL for the healthy subjects, at 56.28 µg/mL for KC1, and at 8.7 µg/mL for KC2 patient. Application of LF-CLs counteracted KC tear cytotoxicity restoring viability obtained in the presence of control tears. Therapeutic contact lenses obtained by LF loading can reduce oxidative stress induced by patients' tears and might represent an efficient device to arrest the progression of keratoconus.
Assuntos
Anti-Infecciosos/administração & dosagem , Apoproteínas/administração & dosagem , Lentes de Contato Hidrofílicas , Portadores de Fármacos , Células Epiteliais/efeitos dos fármacos , Ceratocone/metabolismo , Lactoferrina/administração & dosagem , Lágrimas/fisiologia , Adulto , Antioxidantes/administração & dosagem , Células Epiteliais/metabolismo , Feminino , Humanos , Ferro/metabolismo , Rim/citologia , Masculino , Estresse Oxidativo/fisiologiaRESUMO
Despite transferrin being the main circulating carrier of iron in body fluids, and iron overload conditions being known to worsen stroke outcome through reactive oxygen species (ROS)-induced damage, the contribution of blood transferrin saturation (TSAT) to stroke brain damage is unknown. The objective of this study was to obtain evidence on whether TSAT determines the impact of experimental ischemic stroke on brain damage and whether iron-free transferrin (apotransferrin, ATf)-induced reduction of TSAT is neuroprotective. We found that experimental ischemic stroke promoted an early extravasation of circulating iron-loaded transferrin (holotransferrin, HTf) to the ischemic brain parenchyma. In vitro, HTf was found to boost ROS production and to be harmful to primary neuronal cultures exposed to oxygen and glucose deprivation. In stroked rats, whereas increasing TSAT with exogenous HTf was detrimental, administration of exogenous ATf and the subsequent reduction of TSAT was neuroprotective. Mechanistically, ATf did not prevent extravasation of HTf to the brain parenchyma in rats exposed to ischemic stroke. However, ATf in vitro reduced NMDA-induced neuronal uptake of HTf and also both the NMDA-mediated lipid peroxidation derived 4-HNE and the resulting neuronal death without altering Ca2+-calcineurin signaling downstream the NMDA receptor. Removal of transferrin from the culture media or blockade of transferrin receptors reduced neuronal death. Together, our data establish that blood TSAT exerts a critical role in experimental stroke-induced brain damage. In addition, our findings suggest that the protective effect of ATf at the neuronal level resides in preventing NMDA-induced HTf uptake and ROS production, which in turn reduces neuronal damage.
Assuntos
Apoproteínas/administração & dosagem , Isquemia Encefálica/tratamento farmacológico , Sobrecarga de Ferro/tratamento farmacológico , Acidente Vascular Cerebral/tratamento farmacológico , Transferrina/administração & dosagem , Animais , Apoproteínas/sangue , Isquemia Encefálica/sangue , Isquemia Encefálica/diagnóstico por imagem , Isquemia Encefálica/patologia , Desferroxamina/administração & dosagem , Feminino , Humanos , Ferro/sangue , Sobrecarga de Ferro/sangue , Sobrecarga de Ferro/patologia , Peroxidação de Lipídeos/efeitos dos fármacos , Masculino , Neurônios/metabolismo , Neurônios/patologia , Ratos , Espécies Reativas de Oxigênio/sangue , Receptores da Transferrina/sangue , Acidente Vascular Cerebral/sangue , Acidente Vascular Cerebral/diagnóstico por imagem , Acidente Vascular Cerebral/patologia , Transferrina/metabolismoRESUMO
Individuals with Alzheimer's disease (AD) and their caregivers are using supplements in an effort to halt the progression of the disease. Individuals at risk for or fearing Alzheimer's may use these supplements to try to prevent the disease. Senior care pharmacists are accessible and uniquely qualified to answer questions, make recommendations, and attempt to make drug therapy safe and effective for these individuals. With this in mind, it is important to know the data supporting (or not supporting) common supplements marketed toward those with AD. A review of efficacy and safety data, drug interactions, as well as the mechanism of action believed to benefit those with AD of three common supplements (Prevagen, Cerefolin NAC, and the omega-3 polyunsaturated fatty acid DHA), are highlighted.
Assuntos
Acetilcisteína/administração & dosagem , Equorina/administração & dosagem , Doença de Alzheimer/tratamento farmacológico , Apoproteínas/administração & dosagem , Ácidos Graxos Ômega-3/administração & dosagem , Suplementos Nutricionais , Ácidos Graxos Ômega-3/efeitos adversos , Humanos , Proteínas Recombinantes/administração & dosagemRESUMO
The airways of most people with cystic fibrosis are colonized with biofilms of the Gram-negative, opportunistic pathogen Pseudomonas aeruginosa. Delivery of antibiotics directly to the lung in the form of dry powder aerosols offers the potential to achieve high local concentrations directly to the biofilms. Unfortunately, current aerosolised antibiotic regimes are unable to efficiently eradicate these biofilms from the airways. We investigated the ability of the innate antimicrobial, lactoferrin, to enhance the activity of two aminoglycoside antibiotics (tobramycin and gentamicin) against biofilms of P. aeruginosa strain PAO1. Biofilms were prepared in 96 well polystyrene plates. Combinations of the antibiotics and various lactoferrin preparations were spray dried. The bacterial cell viability of the various spray dried combinations was determined. Iron-free lactoferrin (apo lactoferrin) induced a 3-log reduction in the killing of planktonic cell by the aminoglycoside antibiotics (p<0.01) and also reduced both the formation and persistence of P. aeruginosa biofilms (p<0.01). Combinations of lactoferrin and an aminoglycoside displays potential as an effective new therapeutic strategy in the treatment of P. aeruginosa biofilms infections such as those typical of the CF lungs.
Assuntos
Anti-Infecciosos/administração & dosagem , Anti-Infecciosos/farmacologia , Gentamicinas/farmacologia , Lactoferrina/administração & dosagem , Lactoferrina/farmacologia , Tobramicina/farmacologia , Anti-Infecciosos/química , Apoproteínas/administração & dosagem , Apoproteínas/química , Apoproteínas/farmacologia , Biofilmes/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Composição de Medicamentos , Sinergismo Farmacológico , Lactoferrina/química , Pós , Pseudomonas aeruginosa/efeitos dos fármacosRESUMO
This study used the Eri silk nanoparticles (NPs) for delivering apo-bovine lactoferrin (Apo-bLf) (~2% iron saturated) and Fe-bLf (100% iron saturated) in MDA-MB-231 and MCF-7 breast cancer cell lines. Apo-bLf and Fe-bLf-loaded Eri silk NPs with sizes between 200 and 300 nm (±10 nm) showed a significant internalization within 4 hours in MDA-MB-231 cells when compared to MCF-7 cells. The ex vivo loop assay with chitosan-coated Fe-bLf-loaded silk NPs was able to substantiate its future use in oral administration and showed the maximum absorption within 24 hours by ileum. Both Apo-bLf and Fe-bLf induced increase in expression of low-density lipoprotein receptor-related protein 1 and lactoferrin receptor in epidermal growth factor (EGFR)-positive MDA-MB-231 cells, while transferrin receptor (TfR) and TfR2 in MCF-7 cells facilitated the receptor-mediated endocytosis of NPs. Controlled and sustained release of both bLf from silk NPs was shown to induce more cancer-specific cytotoxicity in MDA-MB-231 and MCF-7 cells compared to normal MCF-10A cells. Due to higher degree of internalization, the extent of cytotoxicity and apoptosis was significantly higher in MDA-MB-231 (EGFR+) cells when compared to MCF-7 (EGFR-) cells. The expression of a prominent anticancer target, survivin, was found to be downregulated at both gene and protein levels. Taken together, all the observations suggest the potential use of Eri silk NPs as a delivery vehicle for an anti-cancer milk protein, and indicate bLf for the treatment of breast cancer.
Assuntos
Neoplasias da Mama/tratamento farmacológico , Sistemas de Liberação de Medicamentos/métodos , Lactoferrina/farmacologia , Nanopartículas/administração & dosagem , Seda/química , Animais , Apoproteínas/administração & dosagem , Apoproteínas/farmacologia , Apoptose/efeitos dos fármacos , Neoplasias da Mama/metabolismo , Neoplasias da Mama/patologia , Bovinos , Quitosana/química , Quitosana/metabolismo , Sistemas de Liberação de Medicamentos/instrumentação , Feminino , Humanos , Ferro/química , Lactoferrina/administração & dosagem , Células MCF-7/efeitos dos fármacos , Camundongos , Mariposas/química , Nanopartículas/química , Nanopartículas/metabolismo , Receptores de Superfície Celular/metabolismoRESUMO
Gelatinases play important roles in tumour invasion and metastasis and are thus considered promising targets for cancer therapy. In this study, a new single-chain variable fragment (scFv)-based fusion protein Fv-LDP, composed of the anti-gelatinases scFv and lidamycin apoprotein (LDP), was prepared, and its combination with angiogenesis inhibitor Endostar was then investigated. The fusion protein Fv-LDP specifically bound to various tumour cells, and its binding capability to human pulmonary giant cell carcinoma (PG) cells was higher than that of LDP. Fv-LDP inhibited the expression and secretion of gelatinases and could be internalized into tumour cells via endocytosis. Fv-LDP also suppressed the growth of human hepatoma cells and murine hepatoma 22 transplanted in Kunming mice in various degrees. In addition, Endostar could enhance the synergistic or additive inhibition of Fv-LDP on the growth, migration or invasion of human hepatoma cells shown by a colony formation assay and a transwell-based migration or invasion assay, respectively. In vivo, Fv-LDP/Endostar combination showed a significantly synergistic effect on the growth of a human hepatoma xenograft, with an inhibition rate of 80.8% compared with the Fv-LDP (44.1%) or Endostar (8.9%)-treated group. The above-mentioned results indicate that the fusion protein Fv-LDP is effective against transplantable hepatoma in mice and human hepatoma xenografts in athymic mice. Moreover, Endostar can potentiate the inhibition effect of Fv-LDP on the growth of human hepatoma cells and xenografts. These data will provide a new combined strategy for improving the therapeutic efficacy of treatments for hepatoma or other gelatinase-overexpressing tumours.
Assuntos
Aminoglicosídeos/farmacologia , Carcinoma Hepatocelular/tratamento farmacológico , Endostatinas/farmacologia , Enedi-Inos/farmacologia , Neoplasias Hepáticas/tratamento farmacológico , Anticorpos de Cadeia Única/farmacologia , Aminoglicosídeos/administração & dosagem , Inibidores da Angiogênese/administração & dosagem , Inibidores da Angiogênese/farmacologia , Animais , Apoproteínas/administração & dosagem , Apoproteínas/farmacologia , Carcinoma de Células Gigantes/tratamento farmacológico , Carcinoma de Células Gigantes/enzimologia , Carcinoma de Células Gigantes/patologia , Carcinoma Hepatocelular/enzimologia , Carcinoma Hepatocelular/patologia , Linhagem Celular Tumoral , Sinergismo Farmacológico , Endostatinas/administração & dosagem , Enedi-Inos/administração & dosagem , Feminino , Gelatinases/metabolismo , Humanos , Neoplasias Hepáticas/enzimologia , Neoplasias Hepáticas/patologia , Neoplasias Pulmonares/tratamento farmacológico , Neoplasias Pulmonares/enzimologia , Neoplasias Pulmonares/patologia , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Nus , Proteínas Recombinantes , Anticorpos de Cadeia Única/administração & dosagem , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
Doxorubicin, a potent anticancer drug associated with cardiotoxicity and low oral bioavailability, was loaded into apotransferrin nanoparticles to improve its pharmacological performance. Here, doxorubicin (doxo)-loaded apotransferrin nanoparticles were termed as Apodoxonano, and they were prepared by sol-oil chemistry. The pH-dependent stability of nanoparticles in simulated fluids was evaluated, and the in vitro release was investigated in phosphate-buffered saline. The pharmacokinetic and toxicity studies were conducted in Wistar rats. Nanoparticles have an average size of 75 nm, with 63% entrapment efficiency, at 10 mg w/w of apotransferrin. The particles displayed good pH-dependent stability in the pH range 1.1-7.4, but sensitive at endosomal pH of 5.5, thus facilitating intracellular drug release in endosomes. Multiplex assay showed high transport ability of nano form across epithelial cells (caco-2) when compared to doxo. Moreover, during oral administration, Apodoxonano localizes significantly in esophagus, stomach and small intestine, suggesting that it was absorbed in GI tract through epithelial lining. The drug localization was shown to be significantly lower in the heart reflecting its decreased cardiotoxic nature. The Apodoxonano with a longer bioavailability and a negligible cardiotoxicity can serve as an effective and safe vehicle of drug delivery.
Assuntos
Apoproteínas/administração & dosagem , Doxorrubicina/administração & dosagem , Sistemas de Liberação de Medicamentos/métodos , Absorção Intestinal/efeitos dos fármacos , Nanopartículas/administração & dosagem , Soroalbumina Bovina/administração & dosagem , Transferrina/administração & dosagem , Administração Oral , Animais , Apoproteínas/efeitos adversos , Apoproteínas/metabolismo , Disponibilidade Biológica , Células CACO-2 , Doxorrubicina/efeitos adversos , Doxorrubicina/metabolismo , Humanos , Absorção Intestinal/fisiologia , Masculino , Nanopartículas/efeitos adversos , Distribuição Aleatória , Ratos , Ratos Wistar , Soroalbumina Bovina/efeitos adversos , Soroalbumina Bovina/metabolismo , Transferrina/efeitos adversos , Transferrina/metabolismoRESUMO
Livers exposed to warm ischemia (WI) before transplantation are at risk for primary nonfunction (PNF), graft dysfunction, and ischemic biliary strictures, all associated with ischemia/reperfusion injury (IRI). Our multifactorial approach, Leuven drug protocol (LDP), has been shown to reduce these effects and increase recipient survival in WI/IRI-damaged porcine liver transplantation. The aim was the identification of the molecular mechanisms responsible for the hepatoprotective effects of the LDP. Porcine livers were exposed to 45 minutes of WI, cold-stored for 4 hours, transplanted, and either modulated (LDP group; n = 3) or not modulated (control group; n = 4). In the LDP group, the donor livers were flushed with streptokinase and epoprostenol before cold perfusion; the recipients received intravenous glycine, a-1-acid-glycoprotein, FR167653 (a mitogen-activated protein kinase inhibitor), a-tocopherol, glutathione, and apotransferrin. Liver samples were taken before WI and 1 hour after reperfusion. Gene expression was determined with microarrays and molecular pathways and key regulatory genes were identified. The number of genes changed between baseline and 1 hour after reperfusion was 686 in the LDP group and 325 in the control group. The extra genes in the LDP group belonged predominantly to pathways related to cytokine activity, apoptosis, and cell proliferation. We identified 7 genes that were suppressed in the LDP group. These genes could be linked in part to the administered drugs. New potential drug targets were identified on the basis of genes induced in the control group but unaffected in the LDP group and interactions predicted by the literature. In conclusion, the LDP primarily resulted in the suppression of inflammation-regulating genes in IRI. Furthermore, the microarray technique helped us to identify additional gene targets.
Assuntos
Perfilação da Expressão Gênica/métodos , Transplante de Fígado/efeitos adversos , Análise de Sequência com Séries de Oligonucleotídeos , Complicações Pós-Operatórias/genética , Complicações Pós-Operatórias/prevenção & controle , Substâncias Protetoras/administração & dosagem , Isquemia Quente/efeitos adversos , Animais , Apoproteínas/administração & dosagem , Citoproteção , Modelos Animais de Doenças , Quimioterapia Combinada , Feminino , Regulação da Expressão Gênica/efeitos dos fármacos , Glutationa/administração & dosagem , Glicina/administração & dosagem , Sobrevivência de Enxerto/efeitos dos fármacos , Orosomucoide/administração & dosagem , Complicações Pós-Operatórias/etiologia , Pirazóis/administração & dosagem , Piridinas/administração & dosagem , Reação em Cadeia da Polimerase em Tempo Real , Suínos , Fatores de Tempo , Transferrina/administração & dosagem , alfa-Tocoferol/administração & dosagemRESUMO
OBJECTIVE: To find the effect of apolactoferrin administration on the middle and inner ears after experimentally induced pneumococcal otitis media. DESIGN: Histopathologic and morphometric analysis of the middle and inner ears. SETTING: University of Minnesota, Minneapolis. SUBJECTS: Ten chinchillas. INTERVENTIONS: The middle ear cavities of chinchillas were inoculated bilaterally with type 2 wild-type Streptococcus pneumoniae. Twenty-four hours later, the ears of 5 of the animals were injected with phosphate-buffered saline (PBS) and the other 5 with human apolactoferrin. The animals were killed 24 hours after the last injection. Bacterial counts were made of the middle ear effusions, and the cochleae were processed for histologic analysis. The thickness of the round window membranes and bacterial and inflammatory cell infiltration of the round window membranes, and scala tympani and damage of the hair cells and stria vascularis were compared for these 2 groups of animals. MAIN OUTCOME MEASURES: Comparison of inflammatory and bacterial cells in the middle and inner ears, and damage to inner ear structures. RESULTS: Bacterial plate counts of middle ear effusions (P = .005) and the number of inflammatory cells in the round window membrane (P = .047) were significantly lower in the apolactoferrin group compared with the group treated with PBS. CONCLUSION: Further investigation of apolactoferrin as a nonantibiotic approach for the treatment of otitis media and its complications is needed to confirm its safety and efficacy.
Assuntos
Apoproteínas/farmacologia , Lactoferrina/farmacologia , Otite Média/tratamento farmacológico , Otite Média/microbiologia , Infecções Pneumocócicas/tratamento farmacológico , Animais , Apoproteínas/administração & dosagem , Chinchila , Lactoferrina/administração & dosagem , Otite Média/patologia , Infecções Pneumocócicas/patologia , Streptococcus pneumoniaeRESUMO
Recent advances in genetic and molecular biology have provided greater insight into the biology of acute myeloid leukemia (AML). These investigations have shown that AML is a heterogeneous disease of biologically different entities. Current therapeutic approaches to AML are based on chemotherapy, but the side effects of the drugs used and various complications, including infections and bleeding, are sometimes fatal. In addition, responses to therapy and long-term outcome differ depending on the subentity in question. Therefore, it is essential to develop new therapeutic strategies such as biology adapted treatment based on the individual molecular pathogenesis of AML. Natural compounds appear to be safer than the current chemotherapeutic drugs, and we have therefore sought new potential agents among various natural compounds with the ability to induce the apoptosis of myeloid leukemic cells. Recently, we found that a highly toxic reactive oxygen species (ROS) generated via the hydrogen peroxide/myeloperoxidase [H(2)O(2)/MPO/halide] system by natural compounds induces apoptosis in MPO-positive leukemic cells. This result is of great interest in establishing novel therapeutic approaches to AML mediated through ROS-induced apoptosis of leukemic cells.
Assuntos
Apoproteínas/administração & dosagem , Apoptose/efeitos dos fármacos , Sistemas de Liberação de Medicamentos/métodos , Desenho de Fármacos , Leucemia Mieloide/tratamento farmacológico , Leucemia Mieloide/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Antineoplásicos/administração & dosagem , Expressão Gênica/efeitos dos fármacos , Humanos , Leucemia Mieloide/patologiaRESUMO
Myeloablative conditioning prior to allogeneic stem cell transplantation causes a rapid increase in transferrin saturation and potentially toxic non-transferrin-bound iron (NTBI) in plasma. We have studied the ability of repeatedly administered apotransferrin to maintain this iron in a transferrin-bound form. Twenty adult patients undergoing myeloablative conditioning and allogeneic stem cell transplantation were enrolled to receive apotransferrin with one of three dosage regimens. Ten consecutive patients with the same preconditioning were studied as controls. At the highest dose level, full transferrin saturation and appearance of NTBI were prevented in five of the eight patients. Serum iron increased significantly more in the patients receiving apotransferrin than in the controls and remained elevated until erythropoietic recovery. From the increment of iron saturation and the amount of endogenous and administered apotransferrin, an average 180 mumol of iron per day was bound to transferrin during the first 4 d after the start of the conditioning therapy. Thereafter, iron accumulation levelled off in most patients. The results suggested that about half of the amount of iron normally transported to erythropoiesis was initially released to plasma after induction of the erythroid arrest. Complete iron binding with apotransferrin would apparently require very high apotransferrin doses.
Assuntos
Apoproteínas/administração & dosagem , Transplante de Células-Tronco Hematopoéticas , Ferro/sangue , Transferrina/administração & dosagem , Condicionamento Pré-Transplante , Adolescente , Adulto , Apoproteínas/efeitos adversos , Apoproteínas/uso terapêutico , Relação Dose-Resposta a Droga , Esquema de Medicação , Eritropoese , Humanos , Pessoa de Meia-Idade , Estudos Prospectivos , Transferrina/efeitos adversos , Transferrina/metabolismo , Transferrina/uso terapêuticoRESUMO
BACKGROUND: Lactoferrin, LF, a multifunctional iron- and heparin-binding protein, present in exocrine body secretions and leukocytes, is remarkably resistant to proteolysis. Ingested bovine iron-unsaturated LF, apo-bLF, suppresses VEGF-A-mediated angiogenesis in a previously described rat mesentery angiogenesis assay, possibly explaining, at least in part, its established anticancer effect in rats and mice. METHODS: Using the same experimental system, we have now studied the effect of (i) ingested human apo-LF, apo-hLF, on angiogenesis mediated by VEGF-A and bFGF, (ii) ingested human iron-saturated LF, holo-hLF, on VEGF-A-mediated angiogenesis and (iii) subcutaneous continuously infused apo-hLF on VEGF-A-mediated angiogenesis. RESULTS: Ingested holo-hLF did not affect VEGF-A-mediated angiogenesis. Ingested apo-hLF (from one and the same batch) significantly enhanced VEGF-A-mediated angiogenesis but did not affect bFGF-mediated angiogenesis. Moreover, subcutaneously infused apo-hLF also significantly stimulated VEGF-A-mediated angiogenesis. CONCLUSION: Taken together, the data suggest that apo-hLF exerts a specific proangiogenic effect in VEGF-A-mediated angiogenesis. Clearly, human and bovine apo-LF exert opposite effects on VEGF-A-induced angiogenesis. Differences in molecular features between human and bovine LFs of possible significance for the outcome are discussed. In hypoxia, compensatory collateral circulation is mediated primarily by VEGF-A. We hypothesize that systemically administered apo-hLF may promote collateral blood vessel formation at hypoxic sites in normal tissue, thus counteracting ischemia and infarction.
Assuntos
Apoproteínas/farmacologia , Lactoferrina/farmacologia , Neovascularização Fisiológica/efeitos dos fármacos , Fator A de Crescimento do Endotélio Vascular/farmacologia , Administração Oral , Animais , Animais não Endogâmicos , Apoproteínas/administração & dosagem , Peso Corporal/efeitos dos fármacos , Fator 2 de Crescimento de Fibroblastos/farmacologia , Humanos , Bombas de Infusão , Injeções Subcutâneas , Lactoferrina/administração & dosagem , Masculino , Microcirculação/efeitos dos fármacos , Distribuição Aleatória , Ratos , Ratos Sprague-Dawley , Proteínas Recombinantes/administração & dosagem , Proteínas Recombinantes/farmacologia , Circulação Esplâncnica/efeitos dos fármacosRESUMO
We investigated the effect of free, non-transferrin-bound iron occurring in haematological stem cell transplant patients on growth of Staphylococcus epidermidis in serum in vitro, and prevention of bacterial growth by exogenous apotransferrin. S. epidermidis did not grow in normal serum at inoculated bacterial densities up to 10(3) cfu ml(-1) but slow growth could be detected at higher initial inocula. Addition of free iron abolished the growth-inhibitory effect of serum, whereas addition of apotransferrin again restored it. Appearance of free iron and loss of growth inhibition coincided in patient serum samples taken daily during myeloablative therapy. Intravenously administered apotransferrin effectively bound free iron and restored the growth inhibition in patient sera. The results suggest that exogenous apotransferrin might protect stem cell transplant patients against infections by S. epidermidis and possibly other opportunistic pathogens.
Assuntos
Apoproteínas/administração & dosagem , Ferro/metabolismo , Infecções Oportunistas/prevenção & controle , Infecções Estafilocócicas/prevenção & controle , Staphylococcus epidermidis/efeitos dos fármacos , Transplante de Células-Tronco/efeitos adversos , Transferrina/administração & dosagem , Apoproteínas/metabolismo , Sangue/microbiologia , Contagem de Colônia Microbiana , Humanos , Ferro/sangue , Infecções Oportunistas/microbiologia , Staphylococcus epidermidis/crescimento & desenvolvimento , Transferrina/metabolismoRESUMO
OBJECTIVE: Disturbances of the alveolar surfactant system have been implicated in the pathogenesis of reperfusion injury. The aim of this study was to evaluate the influence of exogenous surfactant administration on surfactant properties in a model of single lung transplantation. METHODS: We performed heterologous, left lung transplantation (+4 degrees C ischemia; 24 hours, Euro-Collins solution) in 6 foxhounds (untreated) and in 6 animals that received calf lung surfactant extract (Alveofact) prior to explantation (only donor lung; 50 mg/kg body weight) and immediately after onset of reperfusion (both lungs, 200 mg/kg body weight). Separate but synchronized ventilation of each lung was performed, in a volume-controlled, pressure-limited mode, with animals in prone position. Bronchoalveolar lavage fluids were collected in pretransplantation lungs (control), after 24 hours of ischemia prior to transplantation (0 hours) and 6 and 12 hours after reperfusion in both the grafts and the recipient native lungs. RESULTS: Ischemic storage per se did not provoke any changes of the surfactant system; however, severe alterations occurred within 6 hours of reperfusion, resulting in a severe loss of surface activity, including a decrease in the percentage of the large surfactant aggregate fraction, reduction of the surfactant apoproteins SP-B and SP-C, the dipalmitoyl molecular species of phosphatidylcholine and phosphatidylglycerol within the large surfactant aggregate fraction. These abnormalities were restricted to the graft, with virtually normal surfactant function and composition being found in the recipient native lung. Surfactant administration fully normalized the biochemical and largely improved the biophysical surfactant properties, alongside maintenance of lung gas exchange properties. CONCLUSIONS: Severe surfactant abnormalities occur exclusively in the graft when performing separate, synchronized ventilation of each lung to attenuate ventilator-induced lung injury. Bronchoscopic surfactant administration provides protection against these abnormalities and may be a therapeutic strategy in lung transplantation.
Assuntos
Transplante de Pulmão , Alvéolos Pulmonares/anormalidades , Animais , Apoproteínas/administração & dosagem , Biomarcadores/análise , Líquido da Lavagem Broncoalveolar/química , Broncoscopia , Modelos Animais de Doenças , Cães , Relação Dose-Resposta a Droga , Feminino , Lipídeos/administração & dosagem , Masculino , Modelos Biológicos , Fosfolipídeos/administração & dosagem , Fosfolipídeos/metabolismo , Complicações Pós-Operatórias/etiologia , Complicações Pós-Operatórias/metabolismo , Complicações Pós-Operatórias/fisiopatologia , Proteínas/metabolismo , Alvéolos Pulmonares/efeitos dos fármacos , Alvéolos Pulmonares/fisiopatologia , Proteínas Associadas a Surfactantes Pulmonares/administração & dosagem , Surfactantes Pulmonares/administração & dosagem , Traumatismo por Reperfusão/etiologia , Traumatismo por Reperfusão/metabolismo , Traumatismo por Reperfusão/fisiopatologia , Índice de Gravidade de Doença , Estatística como Assunto , Tensão Superficial/efeitos dos fármacos , Fatores de Tempo , Transplante HeterólogoRESUMO
We investigated the effect of free, non-transferrin-bound iron occurring in haematological stem cell transplant patients on growth of Staphylococcus epidermidis in serum in vitro, and prevention of bacterial growth by exogenous apotransferrin. S. epidermidis did not grow in normal serum at inoculated bacterial densities up to 10(3) cfu ml(-1) but slow growth could be detected at higher initial inocula. Addition of free iron abolished the growth-inhibitory effect of serum, whereas addition of apotransferrin again restored it. Appearance of free iron and loss of growth inhibition coincided in patient serum samples taken daily during myeloablative therapy. Intravenously administered apotransferrin effectively bound free iron and restored the growth inhibition in patient sera. The results suggest that exogenous apotransferrin might protect stem cell transplant patients against infections by S. epidermidis and possibly other opportunistic pathogens.
Assuntos
Apoproteínas/administração & dosagem , Ferro/metabolismo , Infecções Oportunistas/prevenção & controle , Infecções Estafilocócicas/prevenção & controle , Staphylococcus epidermidis/efeitos dos fármacos , Transplante de Células-Tronco/efeitos adversos , Transferrina/administração & dosagem , Apoproteínas/metabolismo , Sangue/microbiologia , Contagem de Colônia Microbiana , Humanos , Ferro/sangue , Infecções Oportunistas/microbiologia , Staphylococcus epidermidis/crescimento & desenvolvimento , Transferrina/metabolismoRESUMO
After intraperitoneal injection of 100 or 198 mg/kg of human serum apotransferrin (apo TF) to mice 1 day before acute exposure to 6 Gy of gamma-radiation, the number of endogenous CFU in spleen (CFUs) increased 2.5 or 2.6 times respectively. At a dose fo 10 mg/kg of the protein only an increasing tendency was found, whereas a dose of 1 mg/kg was inefficient. A dose of 100 mg/kg of BSA did not show any effect suggesting that non-specific immune response to alien antigen did not contribute to apo TF radiomodifying action. The following mechanisms of the apoTF radiomodifying effect are discussed: 1) the ability of the protein to inactivate Fe3+ ions that reduces the consequences of radiation oxidative stress; 2) the stimulation of proliferation of the exposed bone marrow cells by activation of Fe3+ transport or by Ca2+ mediated mechanism of mitogen signal transduction; 3) changing in the content and ratio of cyclic nucleotides by apo TF stimulation of Ca-calmodulin-dependent phosphodiesterase.
Assuntos
Apoproteínas/farmacologia , Protetores contra Radiação/farmacologia , Baço/efeitos da radiação , Células-Tronco/efeitos dos fármacos , Células-Tronco/efeitos da radiação , Transferrina/farmacologia , Animais , Apoproteínas/administração & dosagem , Células da Medula Óssea/efeitos dos fármacos , Radioisótopos de Césio/farmacologia , Ensaio de Unidades Formadoras de Colônias , Interpretação Estatística de Dados , Raios gama , Humanos , Injeções Intraperitoneais , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Endogâmicos CBA , Mitógenos , Nucleotídeos Cíclicos/metabolismo , Estresse Oxidativo , Transdução de Sinais , Transferrina/administração & dosagemRESUMO
Free radical injury is thought to play a significant role in the pathogenesis of several disease processes in low birth weight premature infants including retinopathy of prematurity and necrotizing enterocolitis. Because iron is a known catalyst in free radical-mediated oxidation reactions, the objectives of the present in vitro studies were to determine whether after exposure to air 1) iron present in infant formula, or that added to human milk or formula as medicinal iron or as iron contained in human milk fortifier, increases free radical and lipid peroxidation products; and 2) recombinant human lactoferrin added to formula or human milk attenuates iron-mediated free radical formation and lipid peroxidation. Before adding medicinal iron to formula and human milk, significantly more ascorbate and alpha-hydroxyethyl radical production and more lipid peroxidation products (i.e. thiobarbituric acid reactive substances, malondialdehyde, and ethane) were observed in formula. After the addition of medicinal iron to either formula or human milk, further increases were observed in free radical and lipid peroxidation products. When iron-containing human milk fortifier was added to human milk, free radicals also increased. In contrast, the addition of apo-recombinant human lactoferrin to formula or human milk decreased the levels of oxidative products when medicinal iron or human milk fortifier was present. We speculate that the presence of greater concentration of iron and the absence of lactoferrin in formula compared with human milk results in greater in vitro generation of free radicals and lipid peroxidation products. Whether iron-containing formula with lactoferrin administered enterally to preterm infants will result in less free radical generation in vivo has yet to be established.
Assuntos
Alimentos Infantis/efeitos adversos , Ferro/efeitos adversos , Lactoferrina/administração & dosagem , Apoproteínas/administração & dosagem , Radicais Livres/efeitos adversos , Radicais Livres/análise , Humanos , Alimentos Infantis/análise , Recém-Nascido , Recém-Nascido Prematuro , Peroxidação de Lipídeos , Leite Humano/química , Oxirredução , Estresse Oxidativo , Proteínas Recombinantes/administração & dosagemRESUMO
Myeloablative treatment results in iron accumulation and the appearance of non-transferrin-bound iron (NTBI) in the circulation, which may contribute to treatment-related organ damage and susceptibility to infections. The aim of this study was to investigate the efficacy of human apotransferrin in the binding of NTBI in patients receiving an allogeneic stem cell transplant after myeloablative conditioning. A single intravenous 100 mg/kg dose of apotransferrin was given to six adult patients on d 3 after the transplantation. Initially, all patients had serum transferrin saturation above 80% and NTBI in their serum. After the apotransferrin injection, serum NTBI became undetectable in all patients and transferrin saturation decreased to 30-50%. Serum transferrin increased by an average of 1.95 g/l. The administered apotransferrin was subsequently converted into monoferric and diferric transferrin forms. NTBI reappeared and transferrin saturation again exceeded 80% 12-48 h after the injection in four patients and after 6 d in one patient. NTBI remained non-detectable for the whole 12 d follow-up period in one patient. The apotransferrin injection was well tolerated and no adverse events with probable association with the apotransferrin were observed. Repeated apotransferrin infusions might completely eliminate NTBI and iron-induced toxicity during myeloablative therapy.