Do epigenetic marks govern bone mass and homeostasis?

Bone is a specialized connective tissue with a calcified extracellular matrix in which cells are embedded. Besides providing the internal support of the body and protection for vital organs, bone also has several important metabolic functions, especially in mineral homeostasis. Far from being a passive tissue, it is continuously being resorbed and formed again throughout life, by a process known as bone remodeling. Bone development and remodeling are influenced by many factors, some of which may be modifiable in the early steps of life. Several studies have shown that environmental factors in uterus and in infancy may modify the skeletal growth pattern, influencing the risk of bone disease in later life. On the other hand, bone remodeling is a highly orchestrated multicellular process that requires the sequential and balanced events of osteoclast-mediated bone resorption and osteoblast-mediated bone formation. These processes are accompanied by specific gene expression patterns which are responsible for the differentiation of the mesenchymal and hematopoietic precursors of osteoblasts and osteoclasts, respectively, and the activity of differentiated bone cells. This review summarizes the current understanding of how epigenetic mechanisms influence these processes and their possible role in common skeletal diseases

Aortoenteric Fistula Causing Syncope and Gastrointestinal Bleeding

Aortoenteric fistula (AEF) is an uncommon and emergency clinical condition of intra-abdominal bleeding. Early diagnosis can be achieved by computed tomography and endoscopy exploration. Surgical reconstruction is an urgent and multidisciplinary treatment and is recommended after the surgical intervention. A 76-year-old man with a history of abdominal aortic aneurysm reconstruction presented to the emergency department with syncope and suspected upper gastrointestinal (GI) bleeding, which began approximately 30 min before. In the hospital, the patient?s condition worsened and he developed cardiac arrest due to massive GI bleeding. The advanced cardiopulmonary resuscitation was initiated and with suspected active aortoenteric communication, an urgent laparoscopy was immediately performed

Papel de los micro-ARNs en enfermedades del metabolismo óseo

RESUMEN: La osteoporosis y la artrosis son enfermedades cada vez más prevalentes en nuestro medio debido al aumento de la esperanza de vida, estando muy influenciadas por factores ambientales y genéticos. El objetivo de este estudio fue determinar la implicación de algunos mecanismos epigenéticos en estas enfermedades, mediante el análisis de expresión de microRNAs. Hemos analizado los microARNs en muestras de hueso de sujetos con osteoporosis (n=8) y artrosis (n=8), determinando las diferencias de expresión en los microRNAs mediante arrays. Encontramos diferencias significativas entre los grupos en 9 de los microARNs analizados. Estos resultados fueron validados en un segundo análisis en el que incluimos muestras de hueso de sujetos con osteoporosis (n=19), artrosis (n=19) y controles (n=6). Analizamos la expresión de aquellos microARNs más destacados en los arrays, que fueron miR-187, miR-193a-3p, miR-210, miR-214 y miR-518f. Había una mayor expresión de miR-518f en pacientes con osteoporosis frente a controles y artrosis, mientras que miR-187 mostraba una mayor expresión en artrosis que en controles y pacientes con osteoporosis. Aunque no hemos podido confirmar en cultivos celulares la funcionalidad de estos microARNs, estos resultados sugieren que miR-518f y miR-187 pueden estar implicados en la patogenia de algunas alteraciones esqueléticas como la osteoporosis y la artrosis.ABSTRACT: The prevalence of osteoporosis and osteoarthritis is increasing in parallel with the increased life expectancy. They are determined by the interplay of environmental and genetic factors. The aim of this study was to determine how epigenetic mechanisms are involved in these diseases, and specifically the analysis of expression of microRNAs. We measured microRNAs in bone samples of patients with osteoporosis (n=8) and osteoarthritis (n=8), using mini-arrays. Significant between group differences were found in 9 of the microRNAs analyzed. These findings were replicated in a second analysis that included bone samples from subjects with osteoporosis (n=19), osteoarthritis (n=19) and controls (n=6). In the replication stage we analyzed the expression of the microRNAs showing the most significant differences in arrays: miR-187, miR-193a-3p, miR-210, miR-214 and miR-518f. We found that miR-518f displayed a significantly higher expression in patients with osteoporosis. On the other hand, miR-187 displayed a signifciantly higher expression in patients with osteoarthritis. Although we could not confirm the functional effects of these microARNs in vitro, our data suggest that miR-518f and miR-187 may participate in the pathogenesis of skeletal disorders, such as osteoporosis and osteoarthritis