RESUMO
Autologous nerve grafts are the current "gold standard" for repairing large nerve gaps. However, they cause morbidity at the donor nerve site and only a limited amount of nerve can be harvested. Nerve conduits are a promising alternative to autografts and can act as guidance cues for the regenerating axons, without the need to harvest donor nerve. Separately, it has been shown that localized delivery of GDNF can enhance axon growth and motor recovery. FK506, an FDA approved small molecule, has also been shown to enhance peripheral nerve regeneration. This paper describes the design of a novel hole-based drug delivery apparatus integrated with a polytetrafluoroethylene (PTFE) nerve conduit for controlled local delivery of a protein such as GDNF or a small molecule such as FK506. The PTFE devices were tested in a diffusion chamber, and the bioactivity of the released media was evaluated by measuring neurite growth of dorsal root ganglions (DRGs) exposed to the released drugs. The drug delivering nerve guide was able to release bioactive concentrations of FK506 or GDNF. Following these tests, optimized drug releasing nerve conduits were implanted across 10 mm sciatic nerve gaps in a BL6 yellow fluorescent protein (YFP) mouse model, where they demonstrated significant improvement in muscle mass, compound muscle action potential, and axon myelination in vivo as compared with nerve conduits without the drug. The drug delivery nerve guide could release drug for extended periods of time and enhance axon growth in vitro and in vivo.
Assuntos
Portadores de Fármacos/administração & dosagem , Fator Neurotrófico Derivado de Linhagem de Célula Glial/administração & dosagem , Traumatismos dos Nervos Periféricos/terapia , Politetrafluoretileno/administração & dosagem , Regeneração , Tacrolimo/administração & dosagem , Alicerces Teciduais , Animais , Modelos Animais de Doenças , Camundongos , Medicina Regenerativa/métodos , Resultado do TratamentoRESUMO
Notch signaling regulates numerous developmental processes, often acting either to promote one cell fate over another or else to inhibit differentiation altogether. In the embryonic pancreas, Notch and its target gene Hes1 are thought to inhibit endocrine and exocrine specification. Although differentiated cells appear to downregulate Hes1, it is unknown whether Hes1 expression marks multipotent progenitors, or else lineage-restricted precursors. Moreover, although rare cells of the adult pancreas express Hes1, it is unknown whether these represent a specialized progenitor-like population. To address these issues, we developed a mouse Hes1(CreERT2) knock-in allele to inducibly mark Hes1(+) cells and their descendants. We find that Hes1 expression in the early embryonic pancreas identifies multipotent, Notch-responsive progenitors, differentiation of which is blocked by activated Notch. In later embryogenesis, Hes1 marks exocrine-restricted progenitors, in which activated Notch promotes ductal differentiation. In the adult pancreas, Hes1 expression persists in rare differentiated cells, particularly terminal duct or centroacinar cells. Although we find that Hes1(+) cells in the resting or injured pancreas do not behave as adult stem cells for insulin-producing beta (ß)-cells, Hes1 expression does identify stem cells throughout the small and large intestine. Together, these studies clarify the roles of Notch and Hes1 in the developing and adult pancreas, and open new avenues to study Notch signaling in this and other tissues.
Assuntos
Fatores de Transcrição Hélice-Alça-Hélice Básicos/metabolismo , Proteínas de Homeodomínio/metabolismo , Pâncreas/metabolismo , Animais , Fatores de Transcrição Hélice-Alça-Hélice Básicos/genética , Diferenciação Celular/genética , Diferenciação Celular/fisiologia , Proteínas de Homeodomínio/genética , Células Secretoras de Insulina/citologia , Células Secretoras de Insulina/metabolismo , Mucosa Intestinal/metabolismo , Intestinos/citologia , Fígado/citologia , Fígado/metabolismo , Camundongos , Camundongos Mutantes , Microscopia de Fluorescência , Pâncreas/embriologia , Células-Tronco/citologia , Células-Tronco/metabolismo , Fatores de Transcrição HES-1RESUMO
BACKGROUND: Peripheral nerve injury can result in muscle atrophy and long-term disability. We hypothesize that creating a side-to-side bridge to link an injured nerve with a healthy nerve will reduce muscle atrophy and improve muscle function. METHODS: Sprague-Dawley rats were divided into four groups (n = 7 per group). Group 1: transection only--a 10-mm gap was created in the proximal tibial nerve; group 2: transected plus repaired--the transected tibial nerve was repaired; group 3: transected plus repaired plus nerve bridge--transected nerve repaired with a distal nerve bridge between the tibial and peroneal nerves via epineurial windows; and group 4: transected plus nerve bridge--transected tibial nerve left unrepaired and distal bridge added. Gait was assessed every 2 wk. At 90 d the following measures were determined: gastrocnemius mass, muscle and nerve nuclear density, and axonal infiltration into the nerve bridge. RESULTS: Groups 3 and 4 had greater improvements in walking track recovery than groups 1 and 2. Group 3's gastrocnemius muscles exhibited the least amount of atrophy. Groups 1, 2, and 4 exhibited greater histologic appearance of muscle breakdown compared with group 3 and control muscle. Finally, most bridges in groups 3 and 4 had neuronal sprouting via the epineurial windows. CONCLUSIONS: Our study demonstrated reduced muscle atrophy with a side-to-side nerve bridge in the setting of peripheral nerve injury. These results support the application of novel side-to-side bridges in combination with traditional end-to-end neurorrhaphy to preserve muscle viability after peripheral nerve injuries.
Assuntos
Músculo Esquelético/inervação , Atrofia Muscular/cirurgia , Transferência de Nervo/métodos , Traumatismos dos Nervos Periféricos/cirurgia , Nervo Fibular/cirurgia , Nervo Tibial/cirurgia , Animais , Atrofia , Modelos Animais de Doenças , Masculino , Músculo Esquelético/patologia , Atrofia Muscular/patologia , Regeneração Nervosa , Traumatismos dos Nervos Periféricos/patologia , Ratos , Ratos Sprague-Dawley , Nervo Tibial/lesõesRESUMO
INTRODUCTION: Gemcitabine, the current standard of care for pancreatic ductal adenocarcinoma (PDA), has a less than 10% partial response rate. Genexol-PM, a modified form of paclitaxel, has been shown to have antitumour effects in clinical trials of metastatic breast and small-lung-cell carcinoma. The aim of the present study was to determine if Genexol would be a beneficial treatment for gemcitabine-resistant PDA. MATERIALS AND METHODS: We measured the in vitro IC50s of gemcitabine and genexol in cell lines sensitive and resistant to gemcitabine. In vivo, animals with orthotopic pancreatic tumours, resistant to gemcitabine, were treated with phosphate-buffered saline (PBS), gemcitabine, Genexol or gemcitabine+Genexol. Tumour progression was monitored using red fluorescent protein imaging. RESULTS: We showed equivalent IC50s for gemcitabine-sensitive and gemcitabine-resistant cell lines when treated with genexol. In vivo treatment with genexol resulted in a greater per cent reduction in tumour size, less metastatic spread and longer survival compared with treatment with gemcitabine. DISCUSSION: Genexol proved to be an effective treatment for gemcitabine-resistant PDA. These data combined with the successful clinical use of genexol in Phase II trials of other malignancies suggests it maybe an effective treatment for pancreatic cancer, specifically for those patients resistant to gemcitabine.
Assuntos
Antineoplásicos Fitogênicos/farmacologia , Carcinoma Ductal Pancreático/tratamento farmacológico , Resistencia a Medicamentos Antineoplásicos , Paclitaxel/farmacologia , Neoplasias Pancreáticas/tratamento farmacológico , Animais , Antimetabólitos Antineoplásicos , Carcinoma Ductal Pancreático/secundário , Linhagem Celular Tumoral , Desoxicitidina/análogos & derivados , Modelos Animais de Doenças , Humanos , Masculino , Camundongos , Camundongos Nus , Neoplasias Pancreáticas/patologia , GencitabinaRESUMO
The objective of this work was to develop a model and understand the diffusion of a drug into and throughout a drug delivering nerve conduit from a surrounding reservoir through a hole in the wall separating the lumen of the conduit and the reservoir. A mathematical model based on Fick's law of diffusion was developed using the finite difference method to understand the drug diffusion and the effect of varying device parameters on the concentration of drug delivered from a hole-based drug delivery device. The mathematical model was verified using a physical microfluidic (µFD) model and an in vitro/in vivo release test using prototype devices. The results of the mathematical model evaluation and microfluidic device testing offered positive insight into the reliability and function of the reservoir and hole-based drug delivering nerve conduit. The mathematical model demonstrated how changing device parameters would change the drug concentration inside the device. It was observed that the drug release in the conduit could be tuned by both concentration scaling and changing the hole size or number of holes. Based on the results obtained from the microfluidic device, the error in the mathematical drug release model was shown to be less than 10% when comparing the data obtained from mathematical model and µFD model. The data highlights the flexibility of having a hole-based drug delivery system, since the drug release can be scaled predictably by changing the device parameters or the concentration of the drug in the reservoir. Graphical abstract .
Assuntos
Sistemas de Liberação de Medicamentos , Preparações Farmacêuticas , Difusão , Liberação Controlada de Fármacos , Reprodutibilidade dos TestesRESUMO
Advances in imaging and early cancer detection have increased interest in magnetic resonance (MR) guided focused ultrasound (MRgFUS) technologies for cancer treatment. MRgFUS ablation treatments could reduce surgical risks, preserve organ tissue and function, and improve patient quality of life. However, surgical resection and histological analysis remain the gold standard to assess cancer treatment response. For non-invasive ablation therapies such as MRgFUS, the treatment response must be determined through MR imaging biomarkers. However, current MR biomarkers are inconclusive and have not been rigorously evaluated against histology via accurate registration. Existing registration methods rely on anatomical features to directly register in vivo MR and histology. For MRgFUS applications in anatomies such as liver, kidney, or breast, anatomical features that are not caused by the treatment are often insufficient to drive direct registration. We present a novel MR to histology registration workflow that utilizes intermediate imaging and does not rely on anatomical MR features being visible in histology. The presented workflow yields an overall registration accuracy of 1.00 ± 0.13 mm. The developed registration pipeline is used to evaluate a common MRgFUS treatment assessment biomarker against histology. Evaluating MR biomarkers against histology using this registration pipeline will facilitate validating novel MRgFUS biomarkers to improve treatment assessment without surgical intervention. While the presented registration technique has been evaluated in a MRgFUS ablation treatment model, this technique could be potentially applied in any tissue to evaluate a variety of therapeutic options.
Assuntos
Ablação por Ultrassom Focalizado de Alta Intensidade/métodos , Processamento de Imagem Assistida por Computador , Imagem por Ressonância Magnética Intervencionista , Neoplasias/terapia , Animais , Linhagem Celular Tumoral/transplante , Modelos Animais de Doenças , Estudos de Viabilidade , Humanos , Necrose/diagnóstico , Necrose/patologia , Neoplasias/diagnóstico por imagem , Neoplasias/patologia , Coelhos , Resultado do TratamentoRESUMO
Hydrogel crosslinking by external stimuli is a versatile strategy to control and modulate hydrogel properties. Besides photonic energy, thermal energy is one of the most accessible external stimuli and widely applicable for many biomedical applications. However, conventional thermal crosslinking systems require a relatively high temperature (over 100 °C) to initiate covalent bond formation. To our knowledge, there has not been a thermally tunable hydrogel crosslinking system suitable for biological applications. This work demonstrates a unique approach to utilize temperature sensitive liposomes to control and modulate hydrogel crosslinking over mild temperature range (below 50 °C). Temperature sensitive liposomes were used to control the release of chemical crosslinkers by moderate temperature changes. The thermally controlled crosslinker release resulted in tunable mechanical and transport properties of the hydrogel. No significant inflammable response observed in the histology results ensured the biocompatibility of the liposome-mediated crosslinkable hydrogel. This work opens new opportunities to implement thermal energy system for control and modulate hydrogel properties.
Assuntos
Hidrogéis , Lipossomos , Hidrogéis/química , TemperaturaRESUMO
Pancreatic ductal adenocarcinoma (PDA) is the fourth most common cause of cancer death in the United States, with a median survival time of only 3-6 months for forty percent of patients. Current treatments are ineffective, and new PDA therapies are urgently needed. In this context, ultrasound-mediated chemotherapy by polymeric micelles and/or nanoemulsion/microbubble encapsulated drugs may offer an innovative approach to PDA treatment. PDA xenografts were orthotopically grown in the pancreas tails of nu/nu mice by surgical insertion of red fluorescence protein (RFP)-transfected MiaPaCa-2 cells. Tumor growth was controlled by fluorescence imaging. Occasional sonographic measurements correlated well with the formal tumor tracking by red fluorescence. Tumor accumulation of paclitaxel-loaded nanoemulsion droplets and droplet-to-bubble transition under therapeutic ultrasound was monitored by diagnostic ultrasound imaging. MiaPaCa-2 tumors manifested resistance to treatment by gemcitabine (GEM). This drug is the gold standard for PDA therapy. The GEM-resistant tumors proved sensitive to paclitaxel. Among six experimental groups studied, the strongest therapeutic effect was exerted by the following drug formulation: GEM + nanodroplet-encapsulated paclitaxel (nbGEN) combined with tumor-directed 1-MHz ultrasound that was applied for 30 s four to five hours after the systemic drug injection. Ultrasound-mediated PDA therapy by either micellar or nanoemulsion encapsulated paclitaxel resulted in substantial suppression of metastases and ascites, suggesting ultrasound-enhanced killing of invasive cancerous cells. However, tumors relapsed after the completion of therapy, indicating survival of some tumor cells. The recurrent tumors manifested development of paclitaxel resistance. Ultrasound imaging suggested nonuniform distribution of nanodroplets in the tumor volume due to irregular vascularization, which may result in the development of zones with subtherapeutic drug concentration. This is implicated as a possible cause of the resistance development, which may be pertinent to various modes of tumor nanotherapy.
Assuntos
Neoplasias Pancreáticas/diagnóstico por imagem , Neoplasias Pancreáticas/tratamento farmacológico , Animais , Antineoplásicos/administração & dosagem , Linhagem Celular Tumoral , Desoxicitidina/administração & dosagem , Desoxicitidina/análogos & derivados , Sistemas de Liberação de Medicamentos , Resistencia a Medicamentos Antineoplásicos , Humanos , Proteínas Luminescentes/genética , Camundongos , Camundongos Nus , Micelas , Microbolhas , Nanopartículas , Paclitaxel/administração & dosagem , Neoplasias Pancreáticas/genética , Proteínas Recombinantes/genética , Transfecção , Ultrassonografia , Ensaios Antitumorais Modelo de Xenoenxerto , Gencitabina , Proteína Vermelha FluorescenteRESUMO
In the version of this article initially published, the label over the bottom schematic in Fig. 1a was "pH > 5.0"; it should have been "pH < 5.0". Further, the original article misspelt the surname of Katrin P. Guillen as "Gullien". These errors have been corrected in the print, PDF and HTML versions of the article.
RESUMO
Pancreatic ductal adenocarcinoma (PDA) was responsible for ~ 44,000 deaths in the United States in 2018 and is the epitome of a recalcitrant cancer driven by a pharmacologically intractable oncoprotein, KRAS1-4. Downstream of KRAS, the RAFâMEKâERK signaling pathway plays a central role in pancreatic carcinogenesis5. However, paradoxically, inhibition of this pathway has provided no clinical benefit to patients with PDA6. Here we show that inhibition of KRASâRAFâMEKâERK signaling elicits autophagy, a process of cellular recycling that protects PDA cells from the cytotoxic effects of KRAS pathway inhibition. Mechanistically, inhibition of MEK1/2 leads to activation of the LKB1âAMPKâULK1 signaling axis, a key regulator of autophagy. Furthermore, combined inhibition of MEK1/2 plus autophagy displays synergistic anti-proliferative effects against PDA cell lines in vitro and promotes regression of xenografted patient-derived PDA tumors in mice. The observed effect of combination trametinib plus chloroquine was not restricted to PDA as other tumors, including patient-derived xenografts (PDX) of NRAS-mutated melanoma and BRAF-mutated colorectal cancer displayed similar responses. Finally, treatment of a patient with PDA with the combination of trametinib plus hydroxychloroquine resulted in a partial, but nonetheless striking disease response. These data suggest that this combination therapy may represent a novel strategy to target RAS-driven cancers.
Assuntos
Autofagia/efeitos dos fármacos , Sistema de Sinalização das MAP Quinases/efeitos dos fármacos , Quinases de Proteína Quinase Ativadas por Mitógeno/antagonistas & inibidores , Neoplasias Pancreáticas/enzimologia , Neoplasias Pancreáticas/patologia , Inibidores de Proteínas Quinases/farmacologia , Proteínas Proto-Oncogênicas B-raf/antagonistas & inibidores , Proteínas ras/metabolismo , Animais , Antígeno CA-19-9/metabolismo , Linhagem Celular Tumoral , Cloroquina/farmacologia , Humanos , Camundongos SCID , Quinases de Proteína Quinase Ativadas por Mitógeno/metabolismo , Proteínas Proto-Oncogênicas B-raf/metabolismo , Piridonas/farmacologia , Pirimidinonas/farmacologia , Ensaios Antitumorais Modelo de Xenoenxerto , Neoplasias PancreáticasRESUMO
OBJECTIVE: We present a mouse model of pancreatic cancer recurrence following "curative" resection using a novel technique of implanting red fluorescent protein transfected tumor cells within a hyaluronan-based synthetic extracellular matrix into the distal pancreas of nude mice. Following "curative" pancreatic resection, we demonstrate postoperative disease recurrence by fluorescence imaging. METHODS: Forty athymic nude mice underwent pancreatic injection with red fluorescent protein transfected MiaPaCa-2 or AsPc-1 cells suspended in a synthetic extracellular matrix. In 20 animals, the distal pancreas and primary tumor were resected at 2 or 5 wk following injection. The remaining 20 mice underwent sham resection. Eight weeks following resection, necropsy and fluorescence imaging were performed to assess disease recurrence. RESULTS: At exploration, 39 of 40 mice had primary tumors. Eighteen of 20 mice were eligible for curative resection. Eight weeks following "curative" resection, 10 of 18 mice had recurrent disease. Of these, six developed local recurrence, two had distant metastases, and two had both. CONCLUSIONS: Using an orthotopic animal model, we are able to reliably develop primary tumors, safely perform "curative" resection, and demonstrate a 56% recurrence rate 8 wk following resection. We confirmed disease-free resection using fluorescence imaging. This model may prove useful for preclinical adjuvant therapeutic trials.
Assuntos
Modelos Animais de Doenças , Recidiva Local de Neoplasia , Neoplasias Pancreáticas/fisiopatologia , Animais , Linhagem Celular Tumoral , Progressão da Doença , Ensaios de Seleção de Medicamentos Antitumorais , Camundongos , Camundongos Nus , Pancreatectomia , Neoplasias Pancreáticas/secundário , Neoplasias Pancreáticas/cirurgiaRESUMO
Individuals with pancreatic cancer have one of the poorest survival rates among the major cancers, suggesting the need to develop new therapeutic approaches. An effective animal model that mimics the progression and metastases of human pancreatic adenocarcinoma does not exist. The goal of this investigation was to develop a model that would compare the growth and metastasis of orthotopically injected pancreatic cancer cells to cells encapsulated within a synthetic extracellular matrix (sECM). The hypotheses tested were that the cells within the sECM would grow more quickly and more frequently develop metastasis to distant organs. MiaPaCa-2 cells expressing red fluorescent protein, either in serum-free media or within a hyaluronan-based hydrogel, were injected into the pancreas of nude mice. Tumors were monitored for 8 weeks via intravital red fluorescent protein imaging. Cells encapsulated within the sECM grew more quickly and produced larger tumors compared with the cells alone. In addition, the cells within the sECM developed metastasis more frequently. Therefore, the encapsulation of human pancreatic cancer cells within an injectable sECM improved the rate of tumor growth and metastasis in an orthotopic mouse model. The advantages of this new approach can be utilized to investigate the mechanisms of tumor progression and test novel therapeutic agents in vivo.
Assuntos
Adenocarcinoma/patologia , Matriz Extracelular/metabolismo , Ácido Hialurônico/análogos & derivados , Neoplasias Experimentais , Neoplasias Pancreáticas/patologia , Polietilenoglicóis/farmacologia , Adenocarcinoma/metabolismo , Adenocarcinoma/secundário , Animais , Modelos Animais de Doenças , Progressão da Doença , Ácido Hialurônico/farmacologia , Masculino , Camundongos , Camundongos Nus , Neoplasias Pancreáticas/metabolismo , Células Tumorais CultivadasRESUMO
Osteoporosis, arthritis, and periodontal disease are common diseases of the skeleton, all of which could benefit from new therapeutic strategies, including targeted drug delivery. While bone is a rigid structure, it is not inert, with the cells of the skeleton being able to repair damage and respond to alterations in mechanical stimuli and various endocrine agents. Several important factors related to bone physiology that could influence the success of a pharmacological treatment include heterogeneity in bone remodeling activities throughout the skeleton, differences in blood supply and local vascularization, and the "blood-bone" barrier. The structural qualities of bone, especially the presence of hydroxyapatite crystals in the bone mineral and the established binding of certain molecules to this mineral phase, including tetracyclines, bisphosphonates, and other chelators, provide unique opportunities to treat skeletal diseases using targeted drug delivery. Additional opportunities exist in targeting sites with contrasting bone surface activities, including surfaces that are inactive, forming new bone or being resorbed. The ultimate key to developing new bone-targeted therapies is to understand and exploit the physiological characteristics at the desired target sites.
Assuntos
Osso e Ossos/fisiologia , Doenças Ósseas/tratamento farmacológico , Remodelação Óssea/fisiologia , Osso e Ossos/irrigação sanguínea , Osso e Ossos/citologia , Cartilagem/citologia , Sistemas de Liberação de Medicamentos , Humanos , Articulações/irrigação sanguínea , Articulações/fisiologiaRESUMO
The spread of intra-abdominal cancers is a vexing clinical problem for which there is no widely effective treatment. We discovered previously that (2E)-3-[(4-tert-butylphenyl)sulfonyl]acrylonitrile (1) induced cancer cell apoptosis during adhesion to normal mesothelial cells which line the peritoneum. We recently demonstrated that the sulfonylacrylonitrile portion of 1 and hydrophobic aryl substitution were essential for pro-apoptotic activity in cancer cells. Here we synthesized a diverse series of analogues of 1 in order to improve the efficacy and pharmaceutical properties. Analogues and 1 were compared in their ability to cause cancer cell death during adhesion to normal mesothelial cell monolayers. Potent analogues identified in the in vitro assay were validated and found to exhibit improved inhibition of intra-abdominal cancer in two clinically relevant murine models of ovarian and pancreatic cancer spread and metastasis, highlighting their potential clinical use as an adjunct to surgical resection of cancers.
Assuntos
Acrilonitrila/farmacologia , Antineoplásicos/farmacologia , Desenho de Fármacos , Neoplasias Ovarianas/tratamento farmacológico , Neoplasias Pancreáticas/tratamento farmacológico , Sulfonas/farmacologia , Acrilonitrila/síntese química , Acrilonitrila/química , Animais , Antineoplásicos/síntese química , Antineoplásicos/química , Apoptose/efeitos dos fármacos , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Relação Dose-Resposta a Droga , Feminino , Células HT29 , Humanos , Camundongos , Estrutura Molecular , Neoplasias Ovarianas/patologia , Neoplasias Ovarianas/secundário , Neoplasias Pancreáticas/patologia , Neoplasias Pancreáticas/secundário , Relação Estrutura-Atividade , Sulfonas/síntese química , Sulfonas/químicaRESUMO
Recent evidence suggests that patients suffering from chronic obstructive pulmonary disease are also at an increased risk of developing osteoporosis. The pathophysiological mechanism(s) linking these progressive diseases is unknown. The goal of this investigation was to determine whether there were alterations in bone mineral density and content, cortical bone structure and strength, and indexes of bone formation and resorption in the elastase-induced emphysematous hamster. At 3 wk after induction of emphysema, the femoral bone mineral content was 8% less (P = 0.026) and the femoral fracture strength was 6% less (P = 0.032) in the emphysematous hamster than in controls. The cortical area was 8.4% less (P = 0.013) and the periosteal mineral appositional rate was 27% less (P = 0.05) than in controls. Additionally, the endocortical eroded surface in the emphysematous group was about twice that in the control group (P = 0.003). Differences in some indexes of bone formation and resorption, paralleled by differences in bone structure and strength, were observed 3 wk after induction of emphysema. These differences in skeletal metabolism and strength may help explain some of the skeletal changes associated with chronic obstructive pulmonary disease in humans.
Assuntos
Densidade Óssea , Fêmur/fisiopatologia , Enfisema Pulmonar/fisiopatologia , Animais , Fenômenos Biomecânicos , Peso Corporal , Cricetinae , Fêmur/metabolismo , Fêmur/patologia , Medidas de Volume Pulmonar , Mesocricetus , Osteogênese , Periósteo/patologia , Enfisema Pulmonar/induzido quimicamente , Enfisema Pulmonar/metabolismo , Enfisema Pulmonar/patologia , Resistência à TraçãoRESUMO
Although there is extensive documentation in the literature regarding the importance of trabecular bone for proximal femoral integrity and fracture resistance, there remain gaps in our understanding of the basic mineral changes that may occur in trabecular bone attributable to aging. It is unclear what age-related changes take place in the trabecular bone of the proximal femur, a common fracture site in the elderly. It has been suggested that some explanation for conflicting reports on cancellous bone may be found at a microscopic level. The goal of this study was to document age-related changes in micromineralization in the proximal femur of Caucasian females using backscattered electron imaging technology. Proximal femurs were obtained from 11 young and 11 elderly females. Sections of bone from the superior and inferior neck and superior and inferior trochanter were analyzed in a scanning electron microscope using the backscatter technique to determine ash percent. Mean ash percent did not change with age in any of the four regions (P > 0.05). However, while the mean ash percent did not change, there was a dramatic increase in variability elderly age group and loss of mineral heterogeneity. This indicates that there are subpopulations with higher or lower ash percents than the mean in the elderly study group in this investigation. While variance changed dramatically, variance within individuals did not change significantly with age (P > 0.05). The results of this study suggest that changes in micromineralization may occur within an individual, adding a possible new dimension to our understanding of fracture risk in the elderly. Future studies should examine a longer population base to confirm this observation.
Assuntos
Envelhecimento/fisiologia , Calcificação Fisiológica , Fêmur/fisiologia , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Cadáver , Feminino , Fêmur/ultraestrutura , Humanos , Processamento de Imagem Assistida por Computador , Microscopia Eletrônica de Varredura , Pessoa de Meia-IdadeRESUMO
The dismal prognosis of pancreatic adenocarcinoma is due in part to a lack of molecular information regarding disease development. Established cell lines remain a useful tool for investigating these molecular events. Here we present a review of available information on commonly used pancreatic adenocarcinoma cell lines as a resource to help investigators select the cell lines most appropriate for their particular research needs. Information on clinical history; in vitro and in vivo growth characteristics; phenotypic characteristics, such as adhesion, invasion, migration, and tumorigenesis; and genotypic status of commonly altered genes (KRAS, p53, p16, and SMAD4) was evaluated. Identification of both consensus and discrepant information in the literature suggests careful evaluation before selection of cell lines and attention be given to cell line authentication.
Assuntos
Neoplasias Pancreáticas/genética , Neoplasias Pancreáticas/patologia , Linhagem Celular Tumoral , Inibidor p16 de Quinase Dependente de Ciclina/genética , Genótipo , Humanos , Fenótipo , Proteínas Proto-Oncogênicas/genética , Proteínas Proto-Oncogênicas p21(ras) , Proteína Smad4/genética , Proteína Supressora de Tumor p53/genética , Proteínas ras/genéticaRESUMO
The paper reports the results of nanotherapy of ovarian, breast, and pancreatic cancerous tumors by paclitaxel-loaded nanoemulsions that convert into microbubbles locally in tumor tissue under the action of tumor-directed therapeutic ultrasound. Tumor accumulation of nanoemulsions was confirmed by ultrasound imaging. Dramatic regression of ovarian, breast, and orthotopic pancreatic tumors was observed in tumor therapy through systemic injections of drug-loaded nanoemulsions combined with therapeutic ultrasound, signifying efficient ultrasound-triggered drug release from tumor-accumulated nanodroplets. The mechanism of drug release in the process of droplet-to-bubble conversion is discussed. No therapeutic effect from the nanodroplet/ultrasound combination was observed without the drug, indicating that therapeutic effect was caused by the ultrasound-enhanced chemotherapeutic action of the tumor-targeted drug, rather than the mechanical or thermal action of ultrasound itself. Tumor recurrence was observed after the completion of the first treatment round; a second treatment round with the same regimen proved less effective, suggesting that drug-resistant cells were either developed or selected during the first treatment round.
Assuntos
Sistemas de Liberação de Medicamentos/métodos , Microbolhas , Neoplasias/tratamento farmacológico , Paclitaxel/administração & dosagem , Paclitaxel/uso terapêutico , Ultrassom , Animais , Neoplasias da Mama/tratamento farmacológico , Carcinoma/tratamento farmacológico , Linhagem Celular Tumoral , Emulsões/química , Emulsões/uso terapêutico , Feminino , Humanos , Camundongos , Neoplasias Ovarianas/tratamento farmacológico , Neoplasias Pancreáticas/tratamento farmacológico , Transição de FaseRESUMO
Postmenopausal bone loss and the possible progression to osteoporosis is a major health concern. Until recently, hormone replacement therapy (HRT) was the standard for preventing the development of osteoporosis and possible hip fractures following menopause. However, because of some adverse effects of HRT, new therapies, lifestyle habits, and nutritional interventions are being developed and better characterized in their ability to prevent bone loss after menopause. One such option is to increase the amount of fish oil consumed in the diet. The goal of the current research was to determine the impact of fish oil supplementation on bone mass, density, formation, and resorption in an aged ovariectomized rat model. Twelve-month-old female retired breeder Sprague-Dawley rats were fed a control (Control) or fish oil (Fish) diet. Two weeks following the introduction of the diets, the rats were either sham-operated (Sham) or bilaterally ovariectomized (OVX). Ten weeks after surgery, indices of bone mass and bone histomorphometry were measured. Bone mineral content (BMC) of the whole femur was significantly higher in the Fish/OVX than in the Control/OVX, and the differences were most pronounced in the distal and proximal ends of the femur. However, the Fish/Sham and the Control/Sham did not differ in the measures of BMC. Although the Control/OVX had significantly lower cortical area and greater endosteal perimeter compared with the Control/Sham, the differences were not significant between the Fish/Sham and the Fish/OVX. In addition, the Fish/OVX had a significantly larger percent double-labeled surface and mineral apposition rate at the endocortical surface than the Control/OVX. Our findings suggest that fish oil supplementation has a positive effect on bone metabolism and might be a possible intervention to slow the loss of bone observed following menopause.
Assuntos
Envelhecimento/fisiologia , Osso e Ossos/metabolismo , Óleos de Peixe/administração & dosagem , Osteogênese/fisiologia , Ovariectomia , Envelhecimento/efeitos dos fármacos , Animais , Peso Corporal/efeitos dos fármacos , Peso Corporal/fisiologia , Densidade Óssea/efeitos dos fármacos , Densidade Óssea/fisiologia , Osso e Ossos/citologia , Osso e Ossos/efeitos dos fármacos , Feminino , Óleos de Peixe/análise , Osteogênese/efeitos dos fármacos , Ratos , Ratos Sprague-DawleyRESUMO
Research has shown that there is a dramatic increase in the fractional area of calcified fibrocartilage from tendon and capsular insertions on the human femoral neck (Vajda and Bloebaum, 1999; Shea et al., 2001b). Additional information regarding the properties of the proximal femur's cortical shell, gained from the use of an animal model, may result in a better understanding of elderly hip fracture since the cortical shell is a significant contributor to the strength of the proximal femur. The objective of the present study was to determine if the greater trochanter's tendon insertions of the human, rat, and sheep differ in terms of morphology and mineralization. The tendons of the greater trochanter of the human, rat, and sheep were observed to insert via a fibrocartilage insertion. The mineral content of the human and sheep calcified fibrocartilage was significantly higher than that of the rat calcified fibrocartilage (P < 0.01). Additionally, the mineral content of the rat cortical bone was significantly higher than that of the human cortical bone (P < 0.01). The mineral content of the calcified fibrocartilage and bone of the human and sheep were not statistically different from each other. There were also more similarities between the bone structure and lacunae density of the human and sheep than between the human and the rat. This suggests that the tendon insertions of the sheep are a better model than the tendon insertions of the rat for the investigation of calcified fibrocartilage in elderly hip fractures.