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1.
Cardiol Young ; : 1-10, 2022 Dec 23.
Artículo en Inglés | MEDLINE | ID: mdl-36562257

RESUMEN

Early surgical intervention in infants with complex CHD results in significant disruptions to their respiratory, gastrointestinal, and nervous systems, which are all instrumental to the development of safe and efficient oral feeding skills. Standardised assessments or treatment protocols are not currently available for this unique population, requiring the clinician to rely on knowledge based on neonatal literature. Clinicians need to be skilled at evaluating and analysing these systems to develop an appropriate treatment plan to improve oral feeding skill and safety, while considering post-operative recovery in the infant with complex CHD. Supporting the family to re-establish their parental role during the hospitalisation and upon discharge is critical to reducing parental stress and oral feeding success.

2.
Cardiol Young ; 31(4): 589-596, 2021 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-33303052

RESUMEN

Congenital heart disease (CHD) is the most common birth defect for infants born in the United States, with approximately 36,000 affected infants born annually. While mortality rates for children with CHD have significantly declined, there is a growing population of individuals with CHD living into adulthood prompting the need to optimise long-term development and quality of life. For infants with CHD, pre- and post-surgery, there is an increased risk of developmental challenges and feeding difficulties. Feeding challenges carry profound implications for the quality of life for individuals with CHD and their families as they impact short- and long-term neurodevelopment related to growth and nutrition, sensory regulation, and social-emotional bonding with parents and other caregivers. Oral feeding challenges in children with CHD are often the result of medical complications, delayed transition to oral feeding, reduced stamina, oral feeding refusal, developmental delay, and consequences of the overwhelming intensive care unit (ICU) environment. This article aims to characterise the disruptions in feeding development for infants with CHD and describe neurodevelopmental factors that may contribute to short- and long-term oral feeding difficulties.


Asunto(s)
Cardiopatías Congénitas , Calidad de Vida , Adulto , Cuidadores , Niño , Emociones , Cardiopatías Congénitas/epidemiología , Humanos , Lactante , Padres
4.
Development ; 138(15): 3179-88, 2011 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-21750029

RESUMEN

During neural tube closure, specialized regions called hinge points (HPs) display dynamic and polarized cell behaviors necessary for converting the neural plate into a neural tube. The molecular bases of such cell behaviors (e.g. apical constriction, basal nuclear migration) are poorly understood. We have identified a two-dimensional canonical BMP activity gradient in the chick neural plate that results in low and temporally pulsed BMP activity at the ventral midline/median hinge point (MHP). Using in vivo manipulations, high-resolution imaging and biochemical analyses, we show that BMP attenuation is necessary and sufficient for MHP formation. Conversely, BMP overexpression abolishes MHP formation and prevents neural tube closure. We provide evidence that BMP modulation directs neural tube closure via the regulation of apicobasal polarity. First, BMP blockade produces partially polarized neural cells, which retain contact with the apical and basal surfaces but where basolateral proteins (LGL) become apically localized and apical junctional proteins (PAR3, ZO1) become targeted to endosomes. Second, direct LGL misexpression induces ectopic HPs identical to those produced by noggin or dominant-negative BMPR1A. Third, BMP-dependent biochemical interactions occur between the PAR3-PAR6-aPKC polarity complex and phosphorylated SMAD5 at apical junctions. Finally, partially polarized cells normally occur at the MHP, their frequencies inversely correlated with the BMP activity gradient in the neural plate. We propose that spatiotemporal modulation of the two-dimensional BMP gradient transiently alters cell polarity in targeted neuronal cells. This ensures that the neural plate is flexible enough to be focally bent and shaped into a neural tube, while retaining overall epithelial integrity.


Asunto(s)
Proteínas Morfogenéticas Óseas/metabolismo , Polaridad Celular , Morfogénesis/fisiología , Tubo Neural/citología , Tubo Neural/embriología , Tubo Neural/fisiología , Transducción de Señal/fisiología , Animales , Proteínas Morfogenéticas Óseas/genética , Diferenciación Celular/fisiología , Embrión de Pollo , Proteínas Recombinantes de Fusión/genética , Proteínas Recombinantes de Fusión/metabolismo , Proteínas Smad/genética , Proteínas Smad/metabolismo
5.
J Diabetes Sci Technol ; 17(4): 878-886, 2023 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-36546602

RESUMEN

BACKGROUND: Type one diabetes (T1D) management is challenging for adolescents and young adults (AYAs) due to physiological changes, psychosocial challenges, and increasing independence, resulting in increased diabetes distress and hemoglobin A1c (HbA1c). Alternative care models that engage AYAs and improve diabetes-related health outcomes are needed. METHODS: A 15-month study evaluated an adaptation of the Colorado Young Adults with T1D (CoYoT1) Care model. CoYoT1 Care includes person-centered care, virtual peer groups, and physician training delivered via telehealth. AYAs (aged 16-25 years) were partially randomized to CoYoT1 or standard care, delivered via telehealth or in-person. As the study was ending, the COVID-19 pandemic forced all AYAs to transition to primarily telehealth appointments. This secondary analysis compares changes in clinic attendance, T1D-related distress, HbA1c, and device use between those who attended more than 50% of diabetes clinic visits via telehealth and those who attended more sessions in-person throughout the course of the study. RESULTS: Out of 68 AYA participants, individuals (n = 39, 57%) who attended most (>50%) study visits by telehealth completed more diabetes care visits (3.3 visits) than those (n = 29, 43%) who primarily attended visits in-person (2.5 visits; P = .007). AYAs who primarily attended visits via telehealth maintained stable physician-related distress, while those who attended more in-person visits reported increases in physician-related distress (P = .03). CONCLUSIONS: Greater usage of telehealth improved AYA engagement with their care, resulting in increased clinic attendance and reduced physician-related diabetes distress. A person-centered care model delivered via telehealth effectively meets the needs of AYAs with T1D.


Asunto(s)
COVID-19 , Diabetes Mellitus Tipo 1 , Médicos , Telemedicina , Humanos , Adolescente , Adulto Joven , Diabetes Mellitus Tipo 1/terapia , Diabetes Mellitus Tipo 1/psicología , Hemoglobina Glucada , Pandemias , COVID-19/epidemiología , Telemedicina/métodos
6.
Diabetes Technol Ther ; 25(9): 589-601, 2023 09.
Artículo en Inglés | MEDLINE | ID: mdl-37335751

RESUMEN

Background: Adolescents and young adults (AYA) from diverse and marginalized backgrounds with type 1 diabetes (T1D) generally have higher hemoglobin A1c (HbA1c) levels and less frequent continuous glucose monitor (CGM) use than AYA from more privileged backgrounds. Further, scant data address the impact of virtual peer groups (VPG) on health-related outcomes for ethnically and racially diverse AYA with T1D. Methods: CoYoT1 to California was a 15-month randomized controlled trial for AYA aged 16-25 years. In this study, AYA were randomized to receive standard care (n = 28), or CoYoT1 care (n = 40), which consisted of person-centered provider visits and bimonthly VPG. VPG were AYA-driven discussions. AYA completed the Diabetes Distress Scale (DDS), Center for Epidemiologic Studies Depression (CES-D), and Diabetes Empowerment Scale-Short Form (DES-SF) scales at baseline and all study visits. Results: Participants were 50% Latinx and 75% publicly insured. Among CoYoT1 care participants, 19 attended at least 1 VPG session (VPG attendees) and 21 did not attend any VPG sessions. VPG attendees participated in 4.1 VPG sessions on average. VPG attendees had a relative reduction in HbA1C (treatment effect -1.08%, effect sizes values [ES] = -0.49, P = 0.04) and increase in CGM use (treatment effect +47%, ES = 1.00, P = 0.02) compared to standard care. VPG participation was not associated with statistically significant changes in DDS, CES-D, and DES-SF scores. Conclusions: In a 15-month randomized controlled trial, AYA with T1D who participated in VPG reported significant improvements in HbA1c and CGM use. Peer interactions may support unmet needs of AYA with T1D from diverse and marginalized backgrounds. ClinicalTrials.gov Identifier: NCT03793673.


Asunto(s)
Diabetes Mellitus Tipo 1 , Humanos , Adolescente , Adulto Joven , Diabetes Mellitus Tipo 1/tratamiento farmacológico , Hemoglobina Glucada , Glucemia , Automonitorización de la Glucosa Sanguínea
7.
Birth Defects Res A Clin Mol Teratol ; 94(10): 804-16, 2012 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-22865775

RESUMEN

BACKGROUND: A critical event in neural tube closure is the formation of median hinge points (MHPs) and dorsolateral hinge points (DLHPs). Together, they buckle the ventral midline and elevate and juxtapose the neural folds for proper neural tube closure. Dynamic cell behaviors occur at hinge points (HPs), but their molecular regulation is largely unexplored. Bone morphogenetic proteins (BMPs) have been implicated in a variety of neural tube closure defects, although the underlying mechanisms are poorly understood. METHODS: In this study, we used in vivo electroporations, high-resolution microscopy, and biochemical analyses to explore the role of BMP signaling in chick midbrain neural tube closure. RESULTS: We identified a cell-cycle-dependent BMP gradient in the midbrain neural plate, which results in low-level BMP activity at the MHP. We show that although BMP signaling does not have a role in midbrain cell-fate specification, its attenuation is necessary and sufficient for MHP formation and midbrain closure. BMP blockade induces MHP formation by regulating apical constriction and basal nuclear migration. Furthermore, BMP signaling is critically important for maintaining epithelial organization by biochemically interacting with apicobasal polarity proteins (e.g., PAR3). As a result, prolonged BMP blockade disrupts apical junctions, desegregating the apical (PAR3(+), ZO1(+)) and basolateral (LGL(+)) compartments. Direct apical LGL-GFP misexpression in turn is sufficient to induce ectopic HPs. CONCLUSIONS: BMPs have a critical role in maintaining epithelial organization, a role that is conserved across species and tissue types. Its cell-cycle-dependent modulation in the neural plate dynamically regulates apicobasal polarity and helps to bend, shape, and close the neural tube.


Asunto(s)
Tipificación del Cuerpo/genética , Proteínas Morfogenéticas Óseas/fisiología , Cresta Neural/embriología , Tubo Neural/embriología , Neurulación/genética , Animales , Animales Modificados Genéticamente , Proteínas Morfogenéticas Óseas/genética , Proteínas Morfogenéticas Óseas/metabolismo , Movimiento Celular/genética , Movimiento Celular/fisiología , Polaridad Celular/genética , Polaridad Celular/fisiología , Embrión de Pollo , Cinética , Morfogénesis/genética , Morfogénesis/fisiología , Cresta Neural/metabolismo , Placa Neural/citología , Placa Neural/embriología , Placa Neural/metabolismo , Tubo Neural/metabolismo , Defectos del Tubo Neural/embriología , Defectos del Tubo Neural/genética , Neurulación/fisiología , Transducción de Señal/genética , Transducción de Señal/fisiología
8.
J Diabetes Sci Technol ; 16(4): 834-843, 2022 07.
Artículo en Inglés | MEDLINE | ID: mdl-34225480

RESUMEN

BACKGROUND: Diabetes technologies, such as insulin pumps and continuous glucose monitors (CGM), have been associated with improved glycemic control and increased quality of life for young people with type 1 diabetes (T1D); however, few young people use these devices, especially those from minority ethnic groups. Current literature predominantly focuses on white patients with private insurance and does not report experiences of diverse pediatric patients with limited resources. METHODS: To explore potential differences between Latinx and non-Latinx patients, English- and Spanish-speaking young people with T1D (n = 173, ages 11-25 years) were surveyed to assess attitudes about and barriers to diabetes technologies using the Technology Use Attitudes and Barriers to Device Use questionnaires. RESULTS: Both English- and Spanish-speaking participants who identified as Latinx were more likely to have public insurance (P = .0001). English-speaking Latinx participants reported higher Hemoglobin A1c values (P = .003), less CGM use (P = .002), and more negative attitudes about technology (generally, P = .003; and diabetes-specific, P < .001) than either non-Latinx or Spanish-speaking Latinx participants. Barriers were encountered with equivalent frequency across groups. CONCLUSIONS: Latinx English-speaking participants had less positive attitudes toward general and diabetes technology than Latinx Spanish-speaking and non-Latinx English-speaking peers, and differences in CGM use were associated with socioeconomic status. Additional work is needed to design and deliver diabetes interventions that are of interest to and supportive of patients from diverse ethnic and language backgrounds.


Asunto(s)
Diabetes Mellitus Tipo 1 , Adolescente , Adulto , Glucemia , Automonitorización de la Glucosa Sanguínea , Niño , Diabetes Mellitus Tipo 1/tratamiento farmacológico , Humanos , Sistemas de Infusión de Insulina , Calidad de Vida , Tecnología , Adulto Joven
9.
J Diabetes Sci Technol ; 16(6): 1419-1427, 2022 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-34328029

RESUMEN

PURPOSE: The purpose of this study was to analyze the impact of virtual group appointments (VGA) on self-reported health-related outcomes and care activities for young adults (YA) with type 1 diabetes (T1D). METHODS: Fifty-three YA (ages 18-25 years) with T1D participated in a randomized controlled trial (RCT) of the Colorado Young Adults with T1D (CoYoT1) Clinic intervention, encompassing telehealth (TH) with or without VGA. Both new patients (n = 32) and those who participated in a pilot phase (n = 26) were randomized to CoYoT1 Clinic (TH+VGA; n = 23) or TH-only (n = 35) and followed for 1 year. YA completed the Diabetes Distress Scale (DDS), Diabetes Strengths and Resilience (D-STAR), Self-Efficacy in Diabetes (SED), Self-Management of Type 1 Diabetes in Adolescence (SMOD-A), Center for Epidemiologic Studies Depression (CES-D), and EuroQol (EQ-5D) scales at baseline and study end. RESULTS: YA were 67% female, 84% white, 10% Latinx, and the mean age was 20.4 years old. At study end, participants in CoYoT1 Clinic reported significantly reduced diabetes distress compared to those in TH-only, who reported increased levels [Effect Size (ES) = -0.40, P = .02]. Specifically, CoYoT1 Clinic participants reported relative reductions in Physician (ES = -2.87, P = .02) and Regimen-related distress (ES = -0.35, P = .01). In addition, participants in CoYoT1 Clinic reported improved self-management of T1D-related problem solving (ES = 0.47, P = .051) and communication with care providers (ES = 0.39, P = .07). CONCLUSIONS: Virtual group attendance in CoYoT1 Clinic was associated with significant improvements in diabetes-related distress. Long-term exposure to VGA should be investigated in YA with T1D and other pediatric chronic conditions.


Asunto(s)
Diabetes Mellitus Tipo 1 , Automanejo , Telemedicina , Adolescente , Femenino , Adulto Joven , Humanos , Niño , Adulto , Masculino , Citas y Horarios , Autoeficacia
10.
J Pediatr Health Care ; 36(5): 430-437, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-35831218

RESUMEN

INTRODUCTION: Glycemic control is challenging for adolescents with type 1 diabetes (T1D). Team Clinic, a shared medical appointment model, has improved psychosocial outcomes in middle school patients with T1D. We aimed to evaluate the costs of delivering Team Clinic. METHOD: Participants were randomized into Team Clinic (n = 44) or usual care (n = 42) groups. RESULTS: We found no significant difference in 6-month total costs per subject ($3,204 [intervention] vs. $3,476 [control]. No significant differences were found in health care use, test strip use, or continuous glucose monitoring and/or pump. The intervention had more clinic visits (2.41 vs. 1.52 times) and a longer length of visit (2.34 vs. 0.74 hr, but no difference in provider time per patient per visit (median, 0.67 vs. 0.68 hr). DISCUSSION: The Team Clinic care model may help young adolescents with T1D improve psychosocial outcomes and increase completion of clinical visits without increasing costs.


Asunto(s)
Diabetes Mellitus Tipo 1 , Adolescente , Instituciones de Atención Ambulatoria , Glucemia , Automonitorización de la Glucosa Sanguínea , Análisis Costo-Beneficio , Diabetes Mellitus Tipo 1/terapia , Humanos
11.
Nutrients ; 13(9)2021 Sep 18.
Artículo en Inglés | MEDLINE | ID: mdl-34579129

RESUMEN

Micronutrients are dietary components important for health and physiological function, and inadequate intake of these nutrients can contribute to poor health outcomes. The risk of inadequate micronutrient intake has been shown to be greater among low-income Hispanics and postpartum and lactating women. Therefore, we aimed to determine the risk of nutrient inadequacies based on preliminary evidence among postpartum, Hispanic women. Risk of micronutrient inadequacy for Hispanic women (29-45 years of age) from the Southern California Mother's Milk Study (n = 188) was assessed using 24 h dietary recalls at 1 and 6 months postpartum and the estimated average requirement (EAR) fixed cut-point approach. Women were considered at risk of inadequate intake for a nutrient if more than 50% of women were consuming below the EAR. The Chronic Disease Risk Reduction (CDRR) value was also used to assess sodium intake. These women were at risk of inadequate intake for folate and vitamins A, D, and E, with 87.0%, 93.4%, 43.8%, and 95% of women consuming less than the EAR for these nutrients, respectively. Lastly, 71.7% of women consumed excess sodium. Results from this preliminary analysis indicate that Hispanic women are at risk of inadequate intake of important micronutrients for maternal and child health.


Asunto(s)
Dieta , Hispánicos o Latinos/estadística & datos numéricos , Lactancia/fisiología , Micronutrientes/deficiencia , Madres/estadística & datos numéricos , Adulto , California/epidemiología , Estudios de Cohortes , Ingestión de Alimentos , Femenino , Humanos , Estudios Longitudinales , Persona de Mediana Edad , Leche Humana , Periodo Posparto/fisiología , Sodio en la Dieta/administración & dosificación
12.
Nutrients ; 13(5)2021 May 12.
Artículo en Inglés | MEDLINE | ID: mdl-34065978

RESUMEN

Non-alcoholic fatty liver disease impacts 15.2% of Hispanic adolescents and can progress to a build-up of scared tissue called liver fibrosis. If diagnosed early, liver fibrosis may be reversible, so it is necessary to understand risk factors. The aims of this study in 59 Hispanic adolescents with obesity were to: (1) identify potential biological predictors of liver fibrosis and dietary components that influence liver fibrosis, and (2) determine if the association between dietary components and liver fibrosis differs by PNPLA3 genotype, which is highly prevalent in Hispanic adolescents and associated with elevated liver fat. We examined liver fat and fibrosis, genotyped for PNPLA3 gene, and assessed diet via 24-h diet recalls. The prevalence of increased fibrosis was 20.9% greater in males, whereas participants with the GG genotype showed 23.7% greater prevalence. Arachidonic acid was associated with liver fibrosis after accounting for sex, genotype, and liver fat (ß = 0.072, p = 0.033). Intakes of several dietary types of unsaturated fat have different associations with liver fibrosis by PNPLA3 genotype after accounting for sex, caloric intake, and liver fat. These included monounsaturated fat (ßCC/CG = -0.0007, ßGG = 0.03, p-value = 0.004), polyunsaturated fat (ßCC/CG = -0.01, ßGG = 0.02, p-value = 0.01), and omega-6 (ßCC/CG = -0.0102, ßGG = 0.028, p-value = 0.01). Results from this study suggest that reduction of arachidonic acid and polyunsaturated fatty acid intake might be important for the prevention of non-alcoholic fatty liver disease progression, especially among those with PNPLA3 risk alleles.


Asunto(s)
Ácido Araquidónico/efectos adversos , Grasas Insaturadas en la Dieta/efectos adversos , Hispánicos o Latinos/genética , Lipasa/genética , Cirrosis Hepática/etiología , Proteínas de la Membrana/genética , Obesidad Infantil/genética , Adiposidad , Adolescente , Niño , Femenino , Genotipo , Hispánicos o Latinos/estadística & datos numéricos , Humanos , Cirrosis Hepática/genética , Masculino , Obesidad Infantil/complicaciones , Obesidad Infantil/metabolismo , Obesidad Infantil/patología
13.
Pediatr Clin North Am ; 67(4): 661-664, 2020 08.
Artículo en Inglés | MEDLINE | ID: mdl-32650864

RESUMEN

Management of type 1 diabetes mellitus for pediatric and young adult patients is well suited for telehealth. Diabetes management requires frequent communication with health care providers as well as the interpretation of many types of data that can be measured in the home and shared virtually to the provider by the patient. Telehealth technologies allow for a safe alternative and/or addition to in-person care for youth with diabetes. Telehealth increases access to health care, saves time and money, and results in improvements in rates of appointment adherence, patient satisfaction, and quality of life.


Asunto(s)
Diabetes Mellitus Tipo 1/terapia , Manejo de la Enfermedad , Telemedicina/métodos , Niño , Humanos , Satisfacción del Paciente , Calidad de Vida
14.
Contemp Clin Trials ; 88: 105896, 2020 01.
Artículo en Inglés | MEDLINE | ID: mdl-31751776

RESUMEN

As more individuals from diverse backgrounds are diagnosed with Type 1 Diabetes (T1D), the need to address resulting disparities in diabetes outcomes among these populations also escalates. Although young adulthood proves challenging for all patients with diabetes, young adults (YA) from racial/ethnic minorities and low socioeconomic backgrounds face even greater T1D management obstacles. The poorer outcomes in these populations drive an urgent need for alternative care models to improve YA's engagement in their T1D clinical care and address barriers to improved health outcomes. Previous telemedicine initiatives for T1D have yielded positive diabetes care results, especially in YA, offering one promising way to reach this high-risk population. To serve these patients better, an established and successful home telehealth group appointment model, "CoYoT1 Clinic" (Colorado Young Adults with T1D), was adapted to provide care to YA with T1D at a large urban children's hospital in Southern California. At this location, ~70% of patients have public/no insurance, and 85% are racial/ethnic minorities. In this paper, we report the process of adapting the CoYoT1 Clinic model and designing a randomized controlled trial (RCT) to evaluate its efficacy. The adapted model uses meticulous study-design methods that incorporate patient advisors, quantitative and qualitative data collection, collaboration with local stakeholders, intervention development, and patient randomization into a factorial design analyzing telemedicine versus in-person and patient-centered versus standard care. The new model addresses the needs of high-risk YA in Southern California, with the goal of increasing access to care, improving follow-up frequency, and strengthening patient and provider satisfaction. The study is registered with ClinicalTrials.gov (Clinical Trials Number: NCT03793673).


Asunto(s)
Diabetes Mellitus Tipo 1/terapia , Etnicidad , Grupos Minoritarios , Citas Médicas Compartidas , Clase Social , Telemedicina/métodos , Adolescente , Negro o Afroamericano , Asiático , Atención a la Salud , Diabetes Mellitus Tipo 1/metabolismo , Femenino , Grupos Focales , Hemoglobina Glucada/metabolismo , Hispánicos o Latinos , Humanos , Masculino , Ensayos Clínicos Controlados Aleatorios como Asunto , Participación de los Interesados , Comunicación por Videoconferencia , Población Blanca , Adulto Joven
15.
Elife ; 62017 10 25.
Artículo en Inglés | MEDLINE | ID: mdl-29068314

RESUMEN

For decades, the mechanism of skeletal patterning along a proximal-distal axis has been an area of intense inquiry. Here, we examine the development of the ribs, simple structures that in most terrestrial vertebrates consist of two skeletal elements-a proximal bone and a distal cartilage portion. While the ribs have been shown to arise from the somites, little is known about how the two segments are specified. During our examination of genetically modified mice, we discovered a series of progressively worsening phenotypes that could not be easily explained. Here, we combine genetic analysis of rib development with agent-based simulations to conclude that proximal-distal patterning and outgrowth could occur based on simple rules. In our model, specification occurs during somite stages due to varying Hedgehog protein levels, while later expansion refines the pattern. This framework is broadly applicable for understanding the mechanisms of skeletal patterning along a proximal-distal axis.


Asunto(s)
Tipificación del Cuerpo , Costillas/embriología , Somitos/embriología , Animales , Perfilación de la Expresión Génica , Proteínas Hedgehog/metabolismo , Histocitoquímica , Ratones , Ratones Noqueados , Modelos Biológicos
16.
J Bone Miner Res ; 30(2): 297-308, 2015 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-25142306

RESUMEN

The clinical need for methods to repair and regenerate large cartilage and bone lesions persists. One way to make new headway is to study skeletal regeneration when it occurs naturally. Cartilage repair is typically slow and incomplete. However, an exception to this observation can be found in the costal cartilages, where complete repair has been reported in humans but the cellular and molecular mechanisms have not yet been characterized. In this study, we establish a novel animal model for cartilage repair using the mouse rib costal cartilage. We then use this model to test the hypothesis that the perichondrium, the dense connective tissue that surrounds the cartilage, is a tissue essential for repair. Our results show that full replacement of the resected cartilage occurs quickly (within 1 to 2 months) and properly differentiates but that repair occurs only in the presence of the perichondrium. We then provide evidence that the rib perichondrium contains a special niche that houses chondrogenic progenitors that possess qualities particularly suited for mediating repair. Label-retaining cells can be found within the perichondrium that can give rise to new chondrocytes. Furthermore, the perichondrium proliferates and thickens during the healing period and when ectopically placed can generate new cartilage. In conclusion, we have successfully established a model for hyaline cartilage repair in the mouse rib, which should be useful for gaining a more detailed understanding of cartilage regeneration and ultimately for developing methods to improve cartilage and bone repair in other parts of the skeleton.


Asunto(s)
Cartílago Articular/fisiología , Regeneración/fisiología , Costillas/fisiología , Adulto , Animales , Ciclo Celular , Humanos , Masculino , Ratones , Modelos Animales , Cicatrización de Heridas
17.
J Vis Exp ; (68)2012 Oct 11.
Artículo en Inglés | MEDLINE | ID: mdl-23092960

RESUMEN

Programmed cell death (PCD) occurs in adults to maintain normal tissue homeostasis and during embryological development to shape tissues and organs(1,2,6,7). During development, toxic chemicals or genetic alterations can cause an increase in PCD or change PCD patterns resulting in developmental abnormalities and birth defects(3-5). To understand the etiology of these defects, the study of embryos can be complemented with in vitro assays that use differentiating embryonic stem (ES) cells. Apoptosis is a well-studied form of PCD that involves both intrinsic and extrinsic signaling to activate the caspase enzyme cascade. Characteristic cell changes include membrane blebbing, nuclear shrinking, and DNA fragmentation. Other forms of PCD do not involve caspase activation and may be the end-result of prolonged autophagy. Regardless of the PCD pathway, dying cells need to be removed. In adults, the immune cells perform this function, while in embryos, where the immune system has not yet developed, removal occurs by an alternative mechanism. This mechanism involves neighboring cells (called "non-professional phagocytes") taking on a phagocytic role-they recognize the 'eat me' signal on the surface of the dying cell and engulf it(8-10). After engulfment, the debris is brought to the lysosome for degradation. Thus regardless of PCD mechanism, an increase in lysosomal activity can be correlated with increased cell death. To study PCD, a simple assay to visualize lysosomes in thick tissues and multilayer differentiating cultures can be useful. LysoTracker dye is a highly soluble small molecule that is retained in acidic subcellular compartments such as the lysosome(11-13). The dye is taken up by diffusion and through the circulation. Since penetration is not a hindrance, visualization of PCD in thick tissues and multi-layer cultures is possible(12,13). In contrast, TUNEL (Terminal deoxynucleotidyl transferase dUTP nick end labeling) analysis(14), is limited to small samples, histological sections, and monolayer cultures because the procedure requires the entry/permeability of a terminal transferase. In contrast to Aniline blue, which diffuses and is dissolved by solvents, LysoTracker Red DND-99 is fixable, bright, and stable. Staining can be visualized with standard fluorescent or confocal microscopy in whole-mount or section using aqueous or solvent-based mounting media(12,13). Here we describe protocols using this dye to look at PCD in normal and sonic hedgehog null mouse embryos. In addition, we demonstrate analysis of PCD in differentiating ES cell cultures and present a simple quantification method. In summary, LysoTracker staining can be a great complement to other methods of detecting PCD.


Asunto(s)
Aminas/química , Apoptosis/fisiología , Células Madre Embrionarias/citología , Coloración y Etiquetado/métodos , Aminas/análisis , Aminas/metabolismo , Animales , Diferenciación Celular/fisiología , Embrión de Mamíferos/citología , Células Madre Embrionarias/metabolismo , Femenino , Masculino , Ratones , Microscopía Confocal , Microscopía Fluorescente , Embarazo
18.
Dev Dyn ; 237(5): 1359-72, 2008 May.
Artículo en Inglés | MEDLINE | ID: mdl-18429041

RESUMEN

Although Hedgehog (HH) signaling plays a critical role in patterning the ventral midbrain, its role in early midbrain specification is not known. We examined the midbrains of sonic hedgehog (Shh) and smoothened (Smo) mutant mice where HH signaling is respectively attenuated and eliminated. We show that some ventral (Evx1+) cell fates are specified in the Shh-/- mouse in a Ptc1- and Gli1-independent manner. HH-independent ventral midbrain induction was further confirmed by the presence of a Pax7-negative ventral midbrain territory in both Shh-/- and Smo-/- mice at and before embryonic day (E) 8.5. Midbrain signaling centers are severely disrupted in the Shh-/- mutant. Interestingly, dorsal markers are up-regulated (Wnt1, Gdf7, Pax7), down-regulated (Lfng), or otherwise altered (Zic1) in the Shh-/- midbrain. Together with the increased cell death seen specifically in Shh-/- dorsal midbrains (E8.5-E9), our results suggest specific regulation of dorsal patterning by SHH, rather than a simple deregulation due to its absence.


Asunto(s)
Proteínas Hedgehog/metabolismo , Mesencéfalo/anatomía & histología , Mesencéfalo/metabolismo , Morfogénesis , Transducción de Señal/fisiología , Animales , Linaje de la Célula , Femenino , Proteínas Hedgehog/genética , Factores de Transcripción de Tipo Kruppel/genética , Factores de Transcripción de Tipo Kruppel/metabolismo , Mesencéfalo/embriología , Ratones , Ratones Noqueados , Neuronas/citología , Neuronas/metabolismo , Receptores Patched , Receptor Patched-1 , Embarazo , Receptores de Superficie Celular/genética , Receptores de Superficie Celular/metabolismo , Receptores Acoplados a Proteínas G/genética , Receptores Acoplados a Proteínas G/metabolismo , Receptor Smoothened , Proteína con Dedos de Zinc GLI1
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