RESUMEN
BACKGROUND: Symptomatic severe aortic stenosis causes substantial morbidity and mortality when left untreated, yet recent data suggest its undertreatment. OBJECTIVE: To evaluate the efficacy of electronic physician notification to facilitate the guideline-directed management of patients with severe aortic stenosis. HYPOTHESIS: We hypothesize that patients with severe aortic stenosis who are in the care of physicians who receive the notification are more likely to undergo aortic valve replacement within one year. METHODS/DESIGN: The Electronic Physician Notification to Facilitate the Recognition and Management of Severe Aortic Stenosis (DETECT AS) trial is a randomized controlled trial and quality improvement initiative designed to evaluate the efficacy of electronic provider notification versus usual clinical care in the management of patients with severe aortic stenosis. Providers ordering an echocardiogram with findings potentially indicative of severe aortic stenosis are randomized to receive electronic notification with customized guideline recommendations for the management of severe aortic stenosis or usual care (no notification). Randomization continues until 940 patients are enrolled. SETTING: Multicentered, academic health system. OUTCOMES: The primary endpoint is the proportion of patients with severe aortic stenosis receiving an aortic valve replacement within one year of the index echocardiogram. Secondary endpoints include mortality, heart failure hospitalization, transthoracic echocardiogram utilization, aortic stenosis billing code, and cardiology/Valve Team referral. CONCLUSION: The DETECT AS trial will provide insight into whether electronic notification of providers on the presence of severe aortic stenosis and associated clinical guideline recommendations will facilitate recognition and guideline-directed management of severe aortic stenosis. TRIAL REGISTRATION: ClinicalTrials.gov, NCT05230225, https://clinicaltrials.gov/ct2/show/NCT05230225.
Asunto(s)
Estenosis de la Válvula Aórtica , Ecocardiografía , Humanos , Estenosis de la Válvula Aórtica/diagnóstico , Estenosis de la Válvula Aórtica/cirugía , Ecocardiografía/métodos , Índice de Severidad de la Enfermedad , Mejoramiento de la Calidad , Implantación de Prótesis de Válvulas Cardíacas/métodos , Manejo de la Enfermedad , Guías de Práctica Clínica como AsuntoRESUMEN
PURPOSE OF REVIEW: The objective of this review is to explore the role of genetics in cardiometabolic drug development. The declining costs of sequencing and the availability of large-scale genomic data have deepened our understanding of cardiometabolic diseases, revolutionizing drug discovery and development methodologies. We highlight four key areas in which genetics is empowering drug development for cardiometabolic disease: (1) identifying drug candidates, (2) anticipating drug target failures, (3) silencing and editing genes, and (4) enriching clinical trials. RECENT FINDINGS: Identifying novel drug targets through genetic discovery studies and the use of genetic variants as indicators of potential drug efficacy and safety have become critical components of cardiometabolic drug discovery. We highlight the successes of genetically-informed therapeutic strategies, such as PCSK9 and ANGPTL3 inhibitors in lipid lowering and the emerging role of polygenic risk scores in improving the efficiency of clinical trials. Additionally, we explore the potential of gene silencing and editing technologies, such as antisense oligonucleotides and small interfering RNA, showcasing their promise in addressing diseases refractory to conventional treatments. In this review, we highlight four use cases that demonstrate the vital role of genetics in cardiometabolic drug development: (1) identifying drug candidates, (2) anticipating drug target failures, (3) silencing and editing genes, and (4) enriching clinical trials. Through these advances, genetics has paved the way to increased efficiency of drug development as well as the discovery of more personalized and effective treatments for cardiometabolic disease.
Asunto(s)
Enfermedades Cardiovasculares , Desarrollo de Medicamentos , Humanos , Enfermedades Cardiovasculares/genética , Enfermedades Cardiovasculares/tratamiento farmacológico , Descubrimiento de Drogas/métodos , AnimalesRESUMEN
OBJECTIVES: To observe the efficacy and side effects of liraglutide in the treatment of type 2 diabetes mellitus (T2DM) patients with severe obstructive sleep apnea (OSA). METHODS: The study conducted in an outpatient setting was a two-center, prospective randomized controlled study. T2DM patients with severe OSA were randomized to the control group (continuous positive airway pressure [CPAP] and drug treatment without liraglutide) or the liraglutide group (CPAP and drug treatment including liraglutide). Demographic and clinical characteristics, sleep-disordered breathing indices, cardiac function indices, and side effects were evaluated and compared between the two groups before and after 3 months. RESULTS: Of 90 patients, 45 were randomized to the intervention arm (with liraglutide) and 45 to the control arm (without liraglutide). One patient in the liraglutide group dropped out of the study on day 8 after enrollment due to obvious gastrointestinal symptoms. No significant differences were found between the two groups in baseline demographics, clinical characteristics, cardiac function indicators, or sleep disorder respiratory indices (P > 0.05). After 3 months, the body mass index (BMI), apnea hypopnea index (AHI), and mean systolic blood pressure in the liraglutide treatment group were significantly lower than those in the control group (P < 0.05). The minimum oxygen saturation was significantly higher in the liraglutide group compared with that in the control group after 3 months of follow-up (P < 0.05). No difference was found between the two groups in the summary of side effects (P > 0.05). CONCLUSIONS: Liraglutide combined with CPAP can effectively reduce BMI, lower mean systolic blood pressure, and improve AHI scores and hypoxia in T2DM patients with severe OSA. Liraglutide did not increase side effects.
Asunto(s)
Diabetes Mellitus Tipo 2 , Síndromes de la Apnea del Sueño , Apnea Obstructiva del Sueño , Humanos , Diabetes Mellitus Tipo 2/tratamiento farmacológico , Liraglutida/efectos adversos , Apnea Obstructiva del Sueño/tratamiento farmacológico , Estudios Prospectivos , Presión de las Vías Aéreas Positiva ContínuaRESUMEN
Exercise training has been demonstrated as an effective therapy for insulin resistance (IR) to relieve skeletal muscle metabolic disorders. Physiologic protective autophagy was found blocked by IR induced severe endoplasmic reticulum (ER) stress, which may lead to progression of IR. However, the mechanisms are not fully understood. Therefore, this study sought to investigate that how exercise training act on IR through an exploration into the mechanism of ER stress and high-fat diet (HFD)-blocked autophagy. A rodent model was adopted in mice via a HFD and an 8-week swim exercise training intervention. The mouse IR model was successfully established through HFD treatment: body mass, adipose weight, HOMA-IR index increased, as well as IRS1, inhibited in the muscle of HFD mice. Moreover, the AMPK/PGC1α pathway was depressed and IRE1, PERK, ATF6-related ER stress signaling was activated in the muscle of HFD mice. While autophagy factors, including BNIP3, LC3II/LC3I, and PINK1, decreased. However, additional 8-week exercise training during HFD was found to reverse all these changes and alleviate IR. Thus, exercise training could facilitate HFD-blocked protective autophagy via the activation of the AMPK/PGC1α pathway to relieve insulin resistance in mice. Our study provides experimental data for the prevention of T2DM and insulin resistance.
Asunto(s)
Dieta Alta en Grasa , Resistencia a la Insulina , Proteínas Quinasas Activadas por AMP/metabolismo , Animales , Autofagia , Dieta Alta en Grasa/efectos adversos , Estrés del Retículo Endoplásmico , Resistencia a la Insulina/fisiología , Ratones , Ratones Endogámicos C57BL , Músculo Esquelético/metabolismo , Coactivador 1-alfa del Receptor Activado por Proliferadores de Peroxisomas gamma/genética , Coactivador 1-alfa del Receptor Activado por Proliferadores de Peroxisomas gamma/metabolismoRESUMEN
BACKGROUND Chinese hawthorn (Crataegus pinnatifida) fruit is a traditional Chinese medicine for treatment of digestive system and cardiovascular diseases. The fruit contains polyphenol compounds, such as epicatechin, that have anti-inflammatory activity. This study aimed to investigate the effects of an alcohol extract of hawthorn fruit (HAE) on inflammation and oxidative stress in rats with doxorubicin-induced chronic heart failure (CHF). MATERIAL AND METHODS Rats were intraperitoneally injected with doxorubicin to induce CHF and subsequently treated with HAE intragastrically once daily for 6 weeks. At the end of the experiment, echocardiographic and hemodynamic parameters were assessed, and enzyme-linked immunoassays were used to detect the levels of cardiac injury markers (brain natriuretic peptide, creatine kinase-MB, aspartate aminotransferase, lactate dehydrogenase, copeptin, and adrenomedullin), oxidative stress markers (glutathione peroxidase and malondialdehyde), and inflammatory cytokines (interleukin [IL]-6, IL-8, IL-1ß, and tumor necrosis factor-a). The IL-1ß, IL-6, glutathione peroxidase-1, and catalase mRNA levels were also measured by quantitative real-time polymerase chain reaction. RESULTS Our findings indicated that HAE exerts a cardioprotective effect, as shown by improved echocardiographic and hemodynamic parameters, decreased activity of serum myocardial enzymes, reduced serum levels of CHF markers, and inhibited inflammatory response in cardiac tissue. In addition, HAE treatment downregulated the mRNA expression of IL-1ß and tumor necrosis factor-alpha and upregulated the mRNA expression of glutathione peroxidase-1 and catalase compared with untreated doxorubicin-induced CHF rats. CONCLUSIONS HAE shows promise for the prevention and treatment of CHF. The cardioprotective effect of HAE appears to be related to inhibition of both the inflammatory response and oxidative stress in vivo.
Asunto(s)
Crataegus/química , Doxorrubicina/efectos adversos , Etanol/química , Frutas/química , Insuficiencia Cardíaca/patología , Inflamación/patología , Estrés Oxidativo/efectos de los fármacos , Extractos Vegetales/farmacología , Adrenomedulina/sangre , Animales , Antioxidantes/metabolismo , Aspartato Aminotransferasas/sangre , Cromatografía Líquida de Alta Presión , Enfermedad Crónica , Creatina Quinasa/sangre , Citocinas/metabolismo , Electrocardiografía , Glutatión Peroxidasa/metabolismo , Glicopéptidos/sangre , Insuficiencia Cardíaca/inducido químicamente , Insuficiencia Cardíaca/tratamiento farmacológico , Insuficiencia Cardíaca/fisiopatología , Pruebas de Función Cardíaca , L-Lactato Deshidrogenasa/sangre , Masculino , Malondialdehído/metabolismo , Péptido Natriurético Encefálico/sangre , Extractos Vegetales/uso terapéutico , Polifenoles/análisis , ARN Mensajero/genética , ARN Mensajero/metabolismo , Ratas WistarRESUMEN
To investigate the distribution, contamination status, and antibiotic resistance of Listeria monocytogenes in four types of retail poultry meat, including chicken, duck, goose, and pigeon, sold in Jiading District, Shanghai, a total of 236 retail poultry meat samples were collected, and L. monocytogenes isolates were obtained for identification and antibiotic susceptibility testing against 14 common antibiotics. Forty-one L. monocytogenes isolates were detected from the 236 retail poultry meat samples, with detection rates of 24.47%, 19.44%, 14.75%, and 4.44% in chicken, goose, duck, and pigeon meat, respectively. Among refrigerated, frozen, and room temperature samples, refrigerated poultry had the highest detection rate at 25.40%, while frozen poultry had the lowest at 13.33%. The detection rate of L. monocytogenes in chicken meat differed significantly between the storage temperatures, while no significant differences were found for other poultry types. No significant differences in detection rates were observed between different retail locations or packaging methods. Isolates exhibited complete resistance to cefoxitin (FOX) and increasing resistance over time to tetracycline (TET) and clindamycin (CLI), while low levels of resistance were found for penicillin (PEN), oxacillin (OXA), and erythromycin (ERY). Resistance to ERY and TET suggests the potential for multidrug resistance. Significant differences in antibiotic resistance profiles were observed among L. monocytogenes from the various poultry types. In summary, contamination status and antibiotic resistance profiles differed among retail chicken, duck, goose, and pigeon meat sold and the resistance rate of strains continues to increase in Jiading District, Shanghai. Targeted control measures should be implemented to reduce the emergence of resistant strains, as retail conditions had minimal impact on L. monocytogenes prevalence in poultry meat.
Asunto(s)
Antibacterianos , Listeria monocytogenes , Animales , Antibacterianos/farmacología , Aves de Corral , Contaminación de Alimentos/análisis , Microbiología de Alimentos , Farmacorresistencia Bacteriana , China , Carne , Tetraciclina , Eritromicina , Pollos , Pruebas de Sensibilidad MicrobianaRESUMEN
Hysteroscopic local endometrial resection and curettage are common surgical procedures. Postoperative arterial thromboembolism is rare. However, coronary and renal embolism after the procedure has never been reported in the literature, so far. We report a 50-year-old woman who developed arterial thromboembolism 4 hours after local endometrial resection and curettage. Thrombus disappeared after anticoagulant therapy was started as soon as possible. How do strange clots form and by what route do they occur in the arterial system?
RESUMEN
Controlling the kinetic processes of self-assembly and switching their kinetic properties according to the changes in external environments are crucial concepts in the field of supramolecular polymers in water for biological and biomedical applications. Here we report a new self-assembling amphiphilic 4-aminoquinoline (4-AQ)-tetraphenylethene (TPE) conjugate that exhibits kinetically controllable stepwise self-assembly and has the ability of switching its kinetic nature in response to pH. The self-assembly process of the 4-AQ amphiphile comprises the formation of sphere-like nanoparticles, a transition to short nanofibers, and their growth to long nanofibers with â¼1 µm length scale at room temperature (RT). The timescale of the self-assembly process differs according to the pH-responsivity of the 4-AQ moiety in a weakly acidic to neutral pH range. Therefore, after aging for 24 h at RT, the 4-AQ amphiphile forms metastable short nanofibers at pH 5.5, while it forms thermodynamically favored long nanofibers at pH 7.4. Moreover, the modulation of nanofiber growth proceeding spontaneously at RT was achieved by switching the kinetic pathway through changing the pH between 7.4 and 5.5.
RESUMEN
To investigate the contamination status, serotype distribution, and drug resistance of Salmonella in poultry sold in Jiading District, Shanghai. Four types of raw poultry meats (chickens, ducks, geese, and pigeons) have been sampled from commercial markets, and potential Salmonella contamination has also been isolated and identified via serotype analysis. Furthermore, resistance of isolated Salmonella toward 14 commonly used antibiotics has also been conducted. Ninety-two Salmonella strains were isolated from 236 commercial poultry samples. The detection rates of Salmonella in pigeon, goose, duck, and chicken were 28.89, 44.44, 39.34, and 38.30%, respectively. The detection rate of Salmonella exhibits considerable variation across different years. The serotype composition of Salmonella in poultry demonstrates annual variability, undergoing significant changes from year to year. The majority serotypes of Salmonella have been revealed as S. Typhimurium, S. Enteritidis, and S. Agona. Relatively higher drug resistance was discovered with nalidixic acid, tetracycline, ampicillin and chloramphenicol, with drug resistance rate as 58.70, 53.25, 44.57, and 38.04%, respectively. Low drug resistance was revealed with cefotaxime, and completely sensitive to imipenem. Significant difference in drug resistance was noted in the Salmonella isolated from meats. Different serotypes of Salmonella strains have also revealed as difference in drug resistance. A total of 15.22% of Salmonella strains were nonresistant to any tested drugs. Multidrug-resistant strains accounted for 36.96% of isolated strains. The highest number of resistant antibiotics can reach 12 kinds of different antibiotics, Salmonella resistance is exhibiting a consistent upward trend overall. AMP-TET or CHL-CFZ drug resistance pattern suggested that the strain was multidrug resistant. The contamination of Salmonella in raw poultry meat samples in Jiading District, Shanghai is serious, and the drug resistance is increasing. The measures taken for epidemic prevention and control have a certain impact on the contamination of Salmonella in poultry meat. Therefore, monitoring and control should be strengthened.
RESUMEN
Aortic endothelial cell dysfunction is an early trigger of atherosclerosis, the major cause of the cardiovascular disease (CVD). Nanomedicines targeting vascular endothelium and lesions hold great promise as therapeutic solutions to vascular disorders. This study investigates the vascular delivery efficacy of polyurethane-polyurea nanocapsules (Puua-NCs) with pH-synchronized shell cationization and redox-triggered release. Fluorescent lipophilic dye DiI was encapsulated into Puua-NCs of variable sizes and concentrations. In vitro cellular uptake studies with human aortic endothelial cells showed that these Puua-NCs were taken up by cells in a dose-dependent manner. In apolipoprotein E-deficient mice fed a Western diet, a model of atherosclerosis, circulating Puua-NCs were stable and accumulated in aortic endothelium and lesions within 24 hours after intravenous administration. Treatment with thiol-reducing and oxidizing reagents disrupted the disulfide bonds on the surface of internalized NCs, triggering disassembly and intracellular cargo release. Ultimately, Puua-NCs are a potential redox-controllable cardiovascular drug delivery system.
RESUMEN
We present a constrained mixture-micturition-growth (CMMG) model for the bladder. It simulates bladder mechanics, voiding function (micturition) and tissue adaptations in response to altered biomechanical conditions. The CMMG model is calibrated with both in vivo and in vitro data from healthy male rat urinary bladders (cystometry, bioimaging of wall structure, mechanical testing) and applied to simulate the growth and remodeling (G&R) response to partial bladder outlet obstruction (BOO). The bladder wall is represented as a multi-layered, anisotropic, nonlinear constrained mixture. A short time scale micturition component of the CMMG model accounts for the active and passive mechanics of voiding. Over a second, longer time scale, G&R algorithms for the evolution of both cellular and extracellular constituents act to maintain/restore bladder (homeostatic) functionality. The CMMG model is applied to a spherical membrane model of the BOO bladder utilizing temporal data from an experimental male rodent model to parameterize and then verify the model. Consistent with the experimental studies of BOO, the model predicts: an initial loss of voiding capacity followed by hypertrophy of SMC to restore voiding function; bladder enlargement; collagen remodeling to maintain its role as a protective sheath; and increased voiding duration with lower average flow rate. This CMMG model enables a mechanistic approach for investigating the bladder's structure-function relationship and its adaption in pathological conditions. While the approach is illustrated with a conceptual spherical bladder model, it provides the basis for application of the CMMG model to anatomical geometries. Such a mechanistic approach has promise as an in silico tool for the rational development of new surgical and pharmacological treatments for bladder diseases such as BOO.
Asunto(s)
Obstrucción del Cuello de la Vejiga Urinaria , Animales , Modelos Animales de Enfermedad , Guanina/análogos & derivados , Masculino , Ratas , Vejiga Urinaria , Obstrucción del Cuello de la Vejiga Urinaria/patología , Micción/fisiología , UrodinámicaRESUMEN
OBJECTIVES: To evaluate the efficacy and safety of intracoronary administration of prourokinase via balloon catheter during primary percutaneous coronary interventions in patients with acute ST-segment elevation myocardial infarction. METHODS: Acute ST-segment elevation myocardial infarction patients underwent primary percutaneous coronary interventions were randomly divided into two groups: intracoronary prourokinase group (n = 125) and control group (n = 135). During primary percutaneous coronary interventions, prourokinase or saline was injected to the distal end of the culprit lesion via balloon catheter after balloon catheter dilatation. Demographic and clinical characteristics, infarct size, myocardial reperfusion, and cardiac functions were evaluated and compared between two groups. Hemorrhagic complications and major averse cardiovascular events (MACE) occurred in the 6-months follow-up were recorded. RESULTS: No significant differences were observed between two groups with respect to baseline demographic, clinical, and thrombolysis in myocardial infarction grade (P > 0.05). In the intracoronary prourokinase group, more patients had ST-segment resolution (>50%) compared with control group (P < 0.05). Patients in the intracoronary prourokinase group showed lower levels of serum CK, creatine kinase-MB fraction, and troponin I than those in control group (P < 0.05). No significant differences in bleeding complications were observed between the two groups (P > 0.05). At 6-months follow-up, there was no statistically different of MACE between the two groups (P > 0.05). CONCLUSIONS: Intracoronary administration of prourokinase via balloon catheter during primary percutaneous coronary interventions effectively improved myocardial perfusion and no increased bleeding in ST-segment elevation myocardial infarction patients.
Asunto(s)
Forma MB de la Creatina-Quinasa/sangre , Hemorragia , Inyecciones Intraarteriales , Infarto del Miocardio con Elevación del ST , Troponina I/sangre , Activador de Plasminógeno de Tipo Uroquinasa , Catéteres Cardíacos , Angiografía Coronaria/métodos , Monitoreo de Drogas , Electrocardiografía/métodos , Femenino , Fibrinolíticos/administración & dosificación , Fibrinolíticos/efectos adversos , Hemorragia/inducido químicamente , Hemorragia/epidemiología , Humanos , Inyecciones Intraarteriales/instrumentación , Inyecciones Intraarteriales/métodos , Masculino , Persona de Mediana Edad , Intervención Coronaria Percutánea/efectos adversos , Intervención Coronaria Percutánea/métodos , Proteínas Recombinantes/administración & dosificación , Proteínas Recombinantes/efectos adversos , Infarto del Miocardio con Elevación del ST/sangre , Infarto del Miocardio con Elevación del ST/diagnóstico , Infarto del Miocardio con Elevación del ST/tratamiento farmacológico , Infarto del Miocardio con Elevación del ST/cirugía , Resultado del Tratamiento , Activador de Plasminógeno de Tipo Uroquinasa/administración & dosificación , Activador de Plasminógeno de Tipo Uroquinasa/efectos adversosRESUMEN
In the aging population, lower urinary tract (LUT) dysfunction is common and often leads to storage and voiding difficulties classified into overlapping symptom syndromes. Despite prevalence and consequences of these syndromes, LUT disorders continue to be undertreated simply because there are few therapeutic options. LUT function and structure were assessed in aged (>25 months) male and female Fischer 344 rats randomized to oral treatment with a purine nucleoside phosphorylase (PNPase inhibitor) 8-aminoguanine (8-AG) or vehicle for 6 weeks. The bladders of aged rats exhibited multiple abnormalities: tactile insensitivity, vascular remodeling, reduced collagen-fiber tortuosity, increased bladder stiffness, abnormal smooth muscle morphology, swelling of mitochondria, and increases in urodamaging purine metabolites. Treatment of aged rats with 8-AG restored all evaluated histological, ultrastructural, and physiological abnormalities toward that of a younger state. 8-AG is an effective treatment that ameliorates key age-related structural and physiologic bladder abnormalities. Because PNPase inhibition blocks metabolism of inosine to hypoxanthine and guanosine to guanine, likely uroprotective effects of 8-AG are mediated by increased bladder levels of uroprotective inosine and guanosine and reductions in urodamaging hypoxanthine and xanthine. These findings demonstrate that 8-AG has translational potential for treating age-associated LUT dysfunctions and resultant syndromes in humans.
Asunto(s)
Envejecimiento/genética , Guanina/análogos & derivados , Purina-Nucleósido Fosforilasa/genética , Enfermedades Urológicas/tratamiento farmacológico , Envejecimiento/efectos de los fármacos , Animales , Modelos Animales de Enfermedad , Femenino , Guanina/farmacología , Humanos , Masculino , Purina-Nucleósido Fosforilasa/antagonistas & inhibidores , Ratas , Vejiga Urinaria/efectos de los fármacos , Vejiga Urinaria/patología , Enfermedades Urológicas/genética , Enfermedades Urológicas/patologíaRESUMEN
INTRODUCTION: Connecting local hemodynamics, biomechanics, and tissue properties in cerebral aneurysms is important for understanding the processes of wall degeneration and subsequent aneurysm progression and rupture. This challenging problem requires integration of data from multiple sources. METHODS: This paper describes the tools and techniques developed to integrate data from multiple sources, including clinical information, 3D imaging, intraoperative videos, ex vivo micro-computed tomography (CT), and multiphoton microscopy. Central to this approach is a 3D tissue model constructed from micro-CT images of aneurysm samples resected during neurosurgery. This model is aligned to vascular models constructed from 3D clinical images and is used to map and compare flow, biomechanics, and tissue data. RESULTS: The approach is illustrated with data of three human intracranial aneurysms. These case studies demonstrated the ability of this approach to study relationships between different factors affecting the aneurysm wall and produced provocative observations that will be further studied with larger series. For instance, "atherosclerotic" and "hyperplastic" looking parts of the aneurysm corresponded to thicker walls and occurred in regions of recirculating flow and low wall shear stress (WSS); thin regions were associated with inflow jets, flow impingement, and high WSS; blebs had walls of varying structures, including calcified, thin, or hyperplastic walls. CONCLUSIONS: The current approach enables the study of interactions of multiple factors thought to be responsible for the progressive degradation and weakening of the aneurysm wall during its evolution.
Asunto(s)
Aneurisma Intracraneal/diagnóstico por imagen , Angiografía Cerebral , Hemodinámica/fisiología , Humanos , Hidrodinámica , Imagenología Tridimensional , Aneurisma Intracraneal/fisiopatologíaRESUMEN
In this work, we re-evaluated long-standing conjectures as to the source of the exceptionally large compliance of the bladder wall. Whereas these conjectures were based on indirect measures of loading mechanisms, in this work we take advantage of advances in bioimaging to directly assess collagen fibers and wall architecture during biaxial loading. A custom biaxial mechanical testing system compatible with multiphoton microscopy was used to directly measure the layer-dependent collagen fiber recruitment in bladder tissue from 9 male Fischer rats (4 adult and 5 aged). As for other soft tissues, the bladder loading curve was exponential in shape and could be divided into toe, transition and high stress regimes. The relationship between collagen recruitment and loading curves was evaluated in the context of the inner (lamina propria) and outer (detrusor smooth muscle) layers. The large extensibility of the bladder was found to be possible due to folds in the wall (rugae) that provide a mechanism for low resistance flattening without any discernible recruitment of collagen fibers throughout the toe regime. For more extensible bladders, as the loading extended into the transition regime, a gradual coordinated recruitment of collagen fibers between the lamina propria layer and detrusor smooth muscle layer was found. A second important finding was that wall extensibility could be lost by premature recruitment of collagen in the outer wall that cut short the toe region. This change was correlated with age. This work provides, for the first time, a mechanistic understanding of the role of collagen recruitment in determining bladder extensibility and capacitance.
Asunto(s)
Colágeno/metabolismo , Vejiga Urinaria/metabolismo , Animales , Fenómenos Biomecánicos , Adaptabilidad , Masculino , Microscopía de Fluorescencia por Excitación Multifotónica , Membrana Mucosa/metabolismo , Músculo Liso/metabolismo , Ratas Endogámicas F344 , Estrés Mecánico , Soporte de PesoRESUMEN
Urodynamic tests are the gold standard for the diagnosis of bladder dysfunction, and the mechanical compliance of the bladder is an important parameter in these tests. The bladder wall has a layered structure, differentially affected by pathology, so knowledge of the contribution and role of these layers and their constituents to overall bladder compliance will enhance interpretation of these clinical tests. In this study we document the functional morphology of the detrusor and lamina propria of the murine bladder wall using a custom in-situ tensile loading system under multiphoton microscopy (MPM) observation in unloaded state and under incremental uniaxial stretch. Features in the stress-stretch curves of bladder samples were then directly related to corresponding MPM images. Collagen organisation across wall depth was quantified using image analysis techniques. The hypothesis that the lamina propria deformed at low strain by unfolding of the rugae and rearranging collagen fibrils was confirmed. A novel 'pocket' feature in the detrusor was observed along with extensive rearrangement of fibrils in two families at different depths, providing higher stiffness at high stretches in the detrusor. The very different deformations of detrusor and lamina propria were accommodated by the highly coiled structure of collagen in the lamina propria. Imaging and mechanical studies presented here allow gross mechanical response to be attributed to specific components of the bladder wall and further, may be used to investigate the impact of microstructural changes due to pathology or aging, and how they impair tissue functionality. STATEMENT OF SIGNIFICANCE: This article reports the first in-situ multiphoton microscopy observations of microstructural deformation under uniaxial tensile loading of ex vivo bladder. We describe collagen rearrangement through the tissue thickness and relate this directly to the stress-stretch behaviour. We confirm for the first time the unfolding of rugae and realignment of fibrils in the lamina propria during extension and the rapid stiffening as two fibril families in the detrusor are engaged. This technique provides new insight into microstructure function and will enhance understanding of the impact of changes due to pathology or aging.
Asunto(s)
Envejecimiento , Microscopía de Fluorescencia por Excitación Multifotónica , Resistencia a la Tracción , Vejiga Urinaria , Urodinámica , Envejecimiento/metabolismo , Envejecimiento/patología , Animales , Masculino , Ratones , Vejiga Urinaria/metabolismo , Vejiga Urinaria/patología , Vejiga Urinaria/fisiopatologíaRESUMEN
BACKGROUND: SMAD proteins have recently been identified as the first family of putative transforming growth factor-beta1 (TGF-beta1) signal transducers. This study was to investigate the effects of TGF-beta1 and signal protein Smad3 on rat cardiac hypertrophy. METHODS: The incorporation of [(3)H]-leucine was measured to determine the hypertrophy of cardiomyocyte incubated with different doses of TGF-beta1 in cultured neonatal cardiomyocytes. The model of rat cardiac hypertrophy was produced with constriction of the abdominal aorta. At different times after the operation, rats were killed, and their left ventricular mass index (LVMI) determined. The mRNA expression of TGF-beta1 and Smad3 of cultured cells and hypertrophic left ventricles were assessed by RT-PCR. The protein expression of Smad3 was assessed by Western blot. RESULTS: In cultured neonatal cardiomyocytes, TGF-beta1 significantly promoted incorporation of [(3)H]-leucine. With the concentration of 3 pg/L, it increased the expression of Smad3 in mRNA and protein levels after 15 minutes, and continued for up to 8 hours of cultured cardiomyocytes. The LVMI and the expression of TGF-beta1 (mRNA) and Smad3 (mRNA and protein) of hypertrophic left ventricle were increased by day 3 after the operation and continued to the 4th week. The peak expression of these was in the second week after operation. CONCLUSION: TGF-beta1 has positive effects on rat cardiomyocyte hypertrophy. Signal protein Smad3 could be related to the pathologic progression of rat cardiac hypertrophy.