Regulation and functions of cell division in the intestinal tissue.

In multicellular organisms, epithelial cells are key elements of tissue organization. In developing epithelial tissues, cellular proliferation and differentiation are under the tight regulation of morphogenetic programs to ensure correct organ formation and functioning. In these processes, proliferation rates and division orientation regulate the speed, timing and direction of tissue expansion but also its proper patterning. Moreover, tissue homeostasis relies on spatio-temporal modulations of daughter cell behavior and arrangement. These aspects are particularly crucial in the intestine, which is one of the most proliferative tissues in adults, making it a very attractive adult organ system to study the role of cell division on epithelial morphogenesis and organ function. Although epithelial cell division has been the subject of intense research for many years in multiple models, it still remains in its infancy in the context of the intestinal tissue. In this review, we focus on the current knowledge on cell division and regulatory mechanisms at play in the intestinal epithelial tissue, as well as their importance in developmental biology and physiopathology.

Integrin-based adhesion compartmentalizes ALK3 of the BMPRII to control cell adhesion and migration.

The spatial organization of cell-surface receptors is fundamental for the coordination of biological responses to physical and biochemical cues of the extracellular matrix. How serine/threonine kinase receptors, ALK3-BMPRII, cooperate with integrins upon BMP2 to drive cell migration is unknown. Whether the dynamics between integrins and BMP receptors intertwine in space and time to guide adhesive processes is yet to be elucidated. We found that BMP2 stimulation controls the spatial organization of BMPRs by segregating ALK3 from BMPRII into ß3 integrin-containing focal adhesions. The selective recruitment of ALK3 to focal adhesions requires ß3 integrin engagement and ALK3 activation. BMP2 controls the partitioning of immobilized ALK3 within and outside focal adhesions according to single-protein tracking and super-resolution imaging. The spatial control of ALK3 in focal adhesions by optogenetics indicates that ALK3 acts as an adhesive receptor by eliciting cell spreading required for cell migration. ALK3 segregation from BMPRII in integrin-based adhesions is a key aspect of the spatio-temporal control of BMPR signaling.

Differential bioactivity of four BMP-family members as function of biomaterial stiffness.

While a soft film itself is not able to induce cell spreading, BMP-2 presented via such soft film (so called "matrix-bound BMP-2") was previously shown to trigger cell spreading, migration and downstream BMP-2 signaling. Here, we used thin films of controlled stiffness presenting matrix-bound BMPs to study the effect of four BMP members (BMP-2, 4, 7, 9) on cell adhesion and differentiation of skeletal progenitors. We performed automated high-content screening of cellular responses, including cell number, cell spreading area, SMAD phosphorylation and alkaline phosphatase activity. We revealed that the cell response to bBMPs is BMP-type specific, and involved certain BMP receptors and beta chain integrins. In addition, this response is stiffness-dependent for several receptors. The basolateral presentation of the BMPs allowed us to discriminate the specificity of cellular response, especiallyd the role of type I and II BMP receptors and of ß integrins in a BMP-type and stiffness-dependent manner. Notably, BMP-2 and BMP-4 were found to have distinct roles, while ALK5, previously known as a TGF-ß receptor was revealed to be involved in the BMP-pathway.

Learning from BMPs and their biophysical extracellular matrix microenvironment for biomaterial design.

It is nowadays well-accepted that the extracellular matrix (ECM) is not a simple reservoir for growth factors but is an organization center of their biological activity. In this review, we focus on the ability of the ECM to regulate the biological activity of BMPs. In particular, we survey the role of the ECM components, notably the glycosaminoglycans and fibrillary ECM proteins, which can be promoters or repressors of the biological activities mediated by the BMPs. We examine how a process called mechano-transduction induced by the ECM can affect BMP signaling, including BMP internalization by the cells. We also focus on the spatio-temporal regulation of the BMPs, including their release from the ECM, which enables to modulate their spatial localization as well as their local concentration. We highlight how biomaterials can recapitulate some aspects of the BMPs/ECM interactions and help to answer fundamental questions to reveal previously unknown molecular mechanisms. Finally, the design of new biomaterials inspired by the ECM to better present BMPs is discussed, and their use for a more efficient bone regeneration in vivo is also highlighted.

Single-cell transcriptional analysis of normal, aberrant, and malignant hematopoiesis in zebrafish.

Hematopoiesis culminates in the production of functionally heterogeneous blood cell types. In zebrafish, the lack of cell surface antibodies has compelled researchers to use fluorescent transgenic reporter lines to label specific blood cell fractions. However, these approaches are limited by the availability of transgenic lines and fluorescent protein combinations that can be distinguished. Here, we have transcriptionally profiled single hematopoietic cells from zebrafish to define erythroid, myeloid, B, and T cell lineages. We also used our approach to identify hematopoietic stem and progenitor cells and a novel NK-lysin 4(+) cell type, representing a putative cytotoxic T/NK cell. Our platform also quantified hematopoietic defects in rag2(E450fs) mutant fish and showed that these fish have reduced T cells with a subsequent expansion of NK-lysin 4(+) cells and myeloid cells. These data suggest compensatory regulation of the innate immune system in rag2(E450fs) mutant zebrafish. Finally, analysis of Myc-induced T cell acute lymphoblastic leukemia showed that cells are arrested at the CD4(+)/CD8(+) cortical thymocyte stage and that a subset of leukemia cells inappropriately reexpress stem cell genes, including bmi1 and cmyb In total, our experiments provide new tools and biological insights into single-cell heterogeneity found in zebrafish blood and leukemia.

Montelukast for the high impact of asthma exacerbations in Venezuela: a practical and valid approach for Latin America?

BACKGROUND: Asthma affects mainly Venezuela's urban and poor majority. Exacerbations bring about a high demand in health services, thus becoming a significant public health problem. In general, asthma control programs (GINA) with use of inhaled steroid medications have proven effective, although their implementation in real life remains cumbersome. Montelukast could be a useful and practical tool for these deprived socioeconomic sectors. METHODS: This real-life pilot study was conducted in a prospective, double blinded, placebo-controlled manner with randomized and parallel groups. Asthmatics that had never used leukotriene modifiers were recruited and followed-up every three months. The main outcome was the number of exacerbations meriting use of nebulized bronchodilators administered by the health care system. RESULTS: Eighty-eight asthmatic patients were enrolled, between children and adults. Groups were comparable in: demographic data, previous use of other medications, ACT scores, pulmonary functions (Wright Peak Flow meter), allergy status (Skin Prick Test) as well as adherence to the prescribed Montelukast treatment. By an intention to treat (ITT), a total of 64 patients were included for analysis. For the three and six months time points the difference between placebo and Montelukast was found to be significant (p < 0.03 and p < 0.04, respectively). Such trends continued for the rest of the year, but without statistical significance, due to patient attrition. CONCLUSIONS: This real-life pilot study shows that a simplified strategy with oral Montelukast was practical and effective in controlling exacerbations in an asthmatic population of a vulnerable community from Caracas. Such an approach reinforces the role of primary care in asthma treatment.

Home/social environment and asthma profiles in a vulnerable community from Caracas: lessons for urban Venezuela?

BACKGROUND: Asthma is a significant public health problem in Venezuela affecting the predominantly urban and poor majority of the population. Information regarding home and the social environment, key elements in asthma, is found to be deficient in these deprived socioeconomic sectors. This study was carried out to depict a life with asthma in this context which has been served over the years by a National Asthma Control Program. METHODS: A survey of families residing in a socioeconomically deprived community of Caracas was carried out with the assumption that this community reflects the image of a life with asthma emanating from our deprived urban areas. Home physical settings were inspected for the following items: moldy walls, floors, ceilings, windows, sewage, garbage disposal, running water, plumbing, electricity, telephone, construction debris, furniture, bathrooms, food storage, and home appliances. In addition, we also gathered information regarding smoking habits, fumes exposure, pets and/or animals, and sighting of roaches and/or rodents. The presence of people with asthma was observed and their status of control was assessed through the asthma control test (ACT). Comparisons were made between families with asthmatics and those without asthmatics. RESULTS: Randomly, 242 of 750 families (32.26%) were surveyed, with "head of family" providing information (75.6%) on most occasions. No significant association was found with respect to the previously explored items in those families with or without the presence of asthmatics. Medically diagnosed asthma was found in 14.91%, with ACT scores of <19 points in two-thirds of these adults and asthmatic children. Asthmatics reported symptoms occurring mostly during the night and an almost exclusive use of rescue medications. Families provided most treatments and children preferred to use the oral route for control medications. Significant work and school absenteeism were detected in more than 50% of these asthmatics. CONCLUSIONS: No physical home environmental/risk factors turned out to be significantly associated with families reporting the presence of asthmatics. The high impact of asthma found in this Caracas slum underscores the realities of Venezuela's impoverished urban majority. To properly address this important challenge, our National Asthma Control Program needs to be reassessed.

Intravitreal bevacizumab for refractory pseudophakic cystoid macular edema: the Pan-American Collaborative Retina Study Group results.

OBJECTIVE: To determine the feasibility, safety, and clinical effect of intravitreal (IVT) bevacizumab (Avastin; Genentech, Inc., San Francisco, CA) in patients with refractory cystoid macular edema (CME) after cataract surgery. DESIGN: Interventional, retrospective, multicenter study. PARTICIPANTS: Thirty-six eyes of 31 patients with refractory CME after cataract surgery and with a mean age of 68.2 years (range, 67-87 years). METHODS: Patients were treated with at least 1 IVT injection of 1.25 or 2.5 mg bevacizumab. Patients were followed up for 12 months. MAIN OUTCOME MEASURES: Best-corrected visual acuity (BCVA) and central macular thickness (CMT) by optical coherence tomography (OCT). RESULTS: Twenty-six eyes (72.2%) demonstrated improvement of BCVA (> or =2 Early Treatment Diabetic Retinopathy Study [ETDRS] lines), and no eye experienced worsening of visual acuity (> or =2 ETDRS lines). Mean baseline BCVA was 20/200 (0.96 logarithm of the minimum angle of resolution [logMAR] units), and the mean 12-month BCVA was 20/80 (0.62 logMAR units; P<0.0001). Optical coherence tomography demonstrated that mean CMT at baseline was 499.9 microm (range, 298-784 microm) and decreased to a mean of 286.1 microm (range, 168-499 microm) at 12 months (P<0.0001). Four (11%) eyes received 2 injections, 10 (27.8%) eyes received 3 injections, 10 (27.8%) eyes received 4 injections, 1 (2.8%) eye received 5 injections, and 1 (2.8%) eye received 6 injections. The mean number of injections was 2.7 (range, 1-6), and the mean interval between injections was 15.1 weeks (range, 4-45 weeks). No ocular or systemic adverse events were observed. CONCLUSIONS: Short-term results suggest that IVT bevacizumab is well tolerated in patients with refractory pseudophakic CME. Treated eyes had a significant improvement in BCVA and decrease in macular thickness by OCT at 12 months.

Intravitreal bevacizumab for diabetic retinopathy.

Diabetic retinopathy (DR) remains the major threat to sight in the working age population. Diabetic macular edema (DME) is a manifestation of DR that produces loss of central vision. Macular edema within 1 disk diameter of the fovea is present in 9% of the diabetic population. Proliferative diabetic retinopathy (PDR) is a major cause of visual loss in diabetic patients. In PDR, the growth of new vessels from the retina or optic nerve, is thought to occur as a result of vascular endothelial growth factor (VEGF) release into the vitreous cavity as a response to ischemia. Furthermore, VEGF increases vessel permeability leading to deposition of proteins in the interstitium that facilitate the process of angiogenesis and macular edema. This review demonstrates multiple benefits of intravitreal bevacizumab on DR including DME and PDR. The results indicate that intravitreal bevacizumab injections may have a beneficial effect on macular thickness and visual acuity (VA), independent of the type of macular edema that is present. Therefore, in the future this new treatment modality could replace or complement focal/grid laser photocoagulation in DME. In addition, in PDR, this new option could be an adjuvant agent to PRP so that more selective therapy may be applied.

[Pars plana vitrectomy, phacoemulsification and intraocular lens implantation for the management of cataract and proliferative diabetic retinopathy: comparison of a combined versus two-step surgical approach]. / Vitrectomía pars plana, facoemulsificación e implante de lente intraocular para el manejo de catarata y retinopatía diabética proliferativa: comparación de técnica quirúrgica combinada versus en dos tiempos.

PURPOSE: To report the intra-and postoperative complications and visual acuity outcomes in pars plana vitrectomy (PPV), phacoemulsification and intraocular lens (IOL) implantation in patients with cataract and proliferative diabetic retinopathy (PDR). A comparison of the combined versus two-step surgical approach is given. METHOD: Retrospective uncontrolled interventional clinical trial. Forty-eight eyes of 48 consecutive patients with PDR were included. Twenty-eight (58.3%) eyes with combined surgery and 20 (41.7%) eyes with sequential surgery were analyzed. RESULTS: Postoperative follow-up time was between 6 and 63 months (mean: 18 months). 1) Combined surgery: Preoperative best-corrected visual acuity (BCVA) ranged from 20/200 to hand motions, and postoperative BCVA ranged from 20/30 to hand motions. BCVA improved in 17 eyes (60.7%), while in 7 (25%) eyes there was no change (> or =2 ETDRS lines) in VA, and in 4 (14.3%) eyes BCVA decreased. Postoperative complications included vitreous hemorrhage (VH) in 10 (35.7%) eyes, and fibrinous exudation in 9 (32.1%) eyes. 2) Two-step surgery: Preoperative BCVA ranged from 10/200 to light perception, and from 20/40 to light perception in the postoperative period. Best-corrected visual acuity improved in 15 (75%) eyes, remained the same in 4 (20%) eyes, and decreased in 1 (5%) eye. Postoperative complications included fibrinous exudation in 6 (30%) eyes, and VH in 3 (15%) eyes. CONCLUSION: Combined PPV, phacoemulsification and IOL implantation as well as the two-step procedure are safe and effective for the management of cataract in PDR. Sequential surgery could be advantageous to BCVA outcomes by minimizing postoperative VH, which is significantly more frequent after combined surgery.

Vitrectomía pars plana, facoemulsificación e implante de lente intraocular para el manejo de catarata y retinopatía diabética proliferativa: comparación de técnica quirúrgica combinada versus en dos tiempos / Pars plana vitrectomy, phacoemulsification and intraocular lens implantation for the management of cataract and proliferative diabetic retinopathy: comparison of a combined versus two-step surgical approach

Propósito: Describir las complicaciones intra- y postoperatorias y los resultados visuales en vitrectomía vía pars plana (VPP), facoemulsificación e implante de lente intraocular (LIO) en pacientes con catarata y retinopatía diabética proliferativa (RDP). Se realizo una comparación de la técnica combinada versus en dos tiempos quirúrgicos. Método: Ensayo clínico intervencional retrospectivo no controlado. Se incluyeron 48 ojos de 48 pacientes consecutivos con RDP. Se analizaron 28 (58,3%) ojos con cirugía combinada y 20 ojos (41,7%) con cirugía secuencial. Resultados: El tiempo de seguimiento postoperatorio fue entre 6 y 63 meses (promedio: 18 meses). 1) Cirugía combinada: Agudeza visual mejor corregida preoperatoria (AVMC) estaba entre 20/200 a movimiento de manos, y AVMC postoperatoria se encontró entre 20/30 a movimiento de manos. En diecisiete (60,7%) ojos la AVMC mejoró, en 7 (25%) ojos no hubo cambios ≥ 2 líneas ETDRS) en la AV y en 4 (14,3%) ojos la AVMC se redujo. Las complicaciones postoperatorias incluyeron hemorragia vítrea (HV) en 10 ojos (35,7%), y exudación fibrinosa en nueve ojos (32,1%). 2) Cirugía en dos tiempos: AVMC preoperatoria entre 10/200 a percepción de luz, y de 20/40 a percepción de luz en el período postoperatorio. La agudeza visual mejor corregida mejoró en 15 (75%) ojos, permaneció igual en cuatro (20%) ojos, y se redujo en un (5%) ojo. Las complicaciones postoperatorias incluyeron exudación fibrinosa en seis (30%) ojos, y HV en tres (15%) ojos. Conclusión: Tanto la cirugía combinada de VPP, facoemulsificación e implante de LIO como el procedimiento en dos tiempos son seguras y efectivas para el manejo de catarata en RDP. La cirugía secuencial podría ser ventajosa para los resultados de AVMC al disminuir la posibilidad de HV postoperatoria, que parece ser más frecuente después de la cirugía combinada

Purpose: To report the intra-and postoperative complications and visual acuity outcomes in pars plana vitrectomy (PPV), phacoemulsification and intraocular lens (IOL) implantation in patients with cataract and proliferative diabetic retinopathy (PDR). A comparison of the combined versus two-step surgical approach is given. Method: Retrospective uncontrolled interventional clinical trial. Forty-eight eyes of 48 consecutive patients with PDR were included. Twenty-eight (58.3%) eyes with combined surgery and 20 (41.7%) eyes with sequential surgery were analyzed. Results: Postoperative follow-up time was between 6 and 63 months (mean: 18 months). 1) Combined surgery: Preoperative best-corrected visual acuity (BCVA) ranged from 20/200 to hand motions, and postoperative BCVA ranged from 20/30 to hand motions. BCVA improved in 17 eyes (60.7%), while in 7 (25%) eyes there was no change ≥ 2 ETDRS lines) in VA, and in 4 (14.3%) eyes BCVA decreased. Postoperative complications included vitreous hemorrhage (VH) in 10 (35.7%) eyes, and fibrinous exudation in 9 (32.1%) eyes. 2) Two-step surgery: Preoperative BCVA ranged from 10/200 to light perception, and from 20/40 to light perception in the postoperative period. Best-corrected visual acuity improved in 15 (75%) eyes, remained the same in 4 (20%) eyes, and decreased in 1 (5%) eye. Postoperative complications included fibrinous exudation in 6 (30%) eyes, and VH in 3 (15%) eyes. Conclusion: Combined PPV, phacoemulsification and IOL implantation as well as the two-step procedure are safe and effective for the management of cataract in PDR. Sequential surgery could be advantageous to BCVA outcomes by minimizing postoperative VH, which is significantly more frequent after combined surgery (Arch Soc Esp Oftalmol 2009; 84: 31-38)

Primary intravitreal bevacizumab for the management of pseudophakic cystoid macular edema: pilot study of the Pan-American Collaborative Retina Study Group.

PURPOSE: To determine the feasibility, safety, and clinical effect of primary intravitreal bevacizumab (Avastin) in patients with cystoid macular edema (CME) after cataract surgery. SETTING: Five institutions in Venezuela, Costa Rica, Puerto Rico, Peru, and Brazil. METHODS: Twenty-eight eyes of 25 patients treated with at least 1 intravitreal injection of 1.25 mg or 2.50 mg of Avastin participated in this interventional retrospective multicenter study at 5 institutions from 5 countries. Baseline and follow-up visits included Early Treatment Diabetic Retinopathy Study (ETDRS) visual acuity testing, optical coherence tomography (OCT) imaging, and ophthalmoscopic examination. RESULTS: The mean follow-up was 32 weeks (range 24 to 52 weeks). Twenty eyes (71.4%) had improved best corrected visual acuity (BCVA) (> or =2 ETDRS lines), and no eye had worse visual acuity (> or =2 ETDRS lines). The BCVA remained stable in 8 eyes (28.6%). The mean baseline BCVA was 20/160 (logMAR = 0.92) and the mean final BCVA, 20/63 (logMAR = 0.50); the difference was statistically significant (P<.0001). The mean central macular thickness at baseline (466.3 microm; range 208 to 784 microm) decreased significantly (264.5 microm; range 176 to 513 microm) by the end of follow-up (P<.0001). Eight eyes (28.6%) required a second injection and 4 (14.3%), a third injection. The mean interval between injections was 13 weeks (range 5 to 26 weeks). No ocular or systemic adverse events were observed. CONCLUSIONS: Short-term results suggest that primary intravitreal Avastin is well tolerated in patients with pseudophakic CME. Treated eyes had a significant improvement in BCVA and decrease in macular thickness by OCT.

Indocyanine-green-mediated photothrombosis (IMP) with intravitreal triamcinolone acetonide for macular edema secondary to group 2A idiopathic parafoveal telangiectasis without choroidal neovascularization: a pilot study.

BACKGROUND: The purpose of this study was to determine the feasibility, safety and clinical effect of indocyanine green (ICG)-mediated photothrombosis (IMP) combined with intravitreal triamcinolone acetonide (IVTA) in patients with macular edema secondary to idiopathic parafoveal telangiectasis (IPFT) group 2A without choroidal neovascularization (CNV). METHODS: Nine eyes of six patients that were treated with IMP immediately followed by IVTA at a dose of 4 mg participated in the study. Patients had a mean follow-up of 23.3 months (range 12-36 months). Patients underwent one or two sessions of IMP combined with IVTA ("study group"). An IVTA-only group of 19 eyes from 14 patients with macular edema secondary to IPFT group 2A that underwent an IVTA 4 mg without IMP ("IVTA-only group") was included for comparison. In addition, a matched control group of 40 eyes from 20 patients selected retrospectively from our medical records with macular edema secondary to IPFT group 2A without any therapy was included ("observation group"). RESULTS: The best-corrected visual acuity (BCVA) remained stable in five eyes (55.5%). Four eyes (44.4%) demonstrated improvement of BCVA (> or = two ETDRS lines), and no eyes experienced worsening of visual acuity (> or = two ETDRS lines). A significant decrease in hyperfluorescence was not seen with fluorescein angiography (FA), however optical coherence tomography (OCT) showed a decrease in the size of inner intraretinal hyporeflective spaces or cystic edema. Two (22.2%) eyes developed an increase in intraocular pressure. However, it was medically controlled with topical anti-glaucoma medications. Cataract developed in five eyes (55.5%). Six of nine eyes (66.6%) required one retreatment during the study period. At the last follow-up (mean 21.1 months, range 12-30 months) in the IVTA-only group, 5 (25.3%) eyes improved BCVA, 11 (57.9%) eyes remained within two lines of baseline BCVA and 3 (15.8%) eyes lost BCVA. In the observation group, with similar follow-up, 87.5% of eyes showed either stabilization or deterioration of BCVA over time. CONCLUSIONS: Combined IMP and IVTA may provide stability or improvement in BCVA and fundus findings in eyes with macular edema secondary to IPFT group 2A without CNV at a minimum follow-up of 12 months.