Ultrastructural differences between synovial sarcoma and solitary fibrous tumor: comparative study in adult patients from the National Cancer Institute of Mexico.

Synovial sarcoma (SS) and solitary fibrous tumor (SFT) are entities with considerable morphological and immunohistochemical similarities that sometimes show a non-confirmatory profile (TLE1 negative, CD34 and focal or negative STAT6 and lack of specific fusion IHC markers), in which the utility ultrastructure is unknown. A cross-sectional, retrospective, analytical, nonexperimental study was carried out by the Department of Pathology of the National Cancer Institute of Mexico (INCan) e from January 1, 2009 to December 31, 2018. With 17 SFT cases with diffuse or focal CD34 and STAT6 positivity and 18 cases of SS with positive FISH molecular test t(X:18) breakapart were studied by electron microscopy of fresh glutaraldehyde fixed or paraffin-embedded tissue. The ultrastructural findings with a significant difference present in the SS were tandem tight junctions, desmosomes and abundance of dilated rough endoplasmic reticulum (RER) cisternae (p < 0.001, 0.003, and 0.001, respectively); while in the (SFT) the presence of abundant glycogen, basal lamina, long and slender cytoplasmic processes, pinocytic vesicles, hemidesmosomes, and/or dense plaques, collagen skein, and microvilli-like buds (p = 0.028, 0.005, and <0.001 for the last five). We then infer that the five distinctive markers of the SFT are the collagen skeins intermingled with cellular processes in a shape of "squid can," and the pinocytic vesicles as they were not observed in any case of SS. Conversely, tandem junctions were not found in any SFT case. Although the presence of multivesicular buds in the SFT was not significant, it had not been previously described.

Myxoinflammatory fibroblastic sarcoma: ultrastructural study of 7 cases.

Since first described, several studies about Myxoinflammatory fibroblastic sarcomas (MIFS) have been published stating the clinicopathological, morphological and immunohistochemical features. However, the ultrastructural findings of these MIFS are limited. Thus, the objective of the present paper is to describe the ultrastructural characteristics of these type of tumors by utilizing tissue that was embedded in paraffin and submitted for immunohistochemistry.The tissue of seven different cases was obtained for ultrastructural study with automatized staining devices, that were later observed by using transmission electron microscopy. Histologically all cases displayed conventional structures of Myxoinflammatory fibroblastic sarcoma (Reed-Sternberg like cells, pseudolipoblasts and emperipolesis). Conversely, two of them exhibited high-grade components, one rich in osteoclastic type giant cells and hypercellular areas, and another one rich in inflammation (Hodgkin-like).After immunohistochemistry, all the samples revealed positivity for CD68 with six cases CD163 and five being positive to CD34, Cyclin-D1, and D2-40. Ultrastructural findings indicated rough endoplasmic reticulum with dilatation of the cisterns that indented the nuclei ("soccer ball" cells), abundant lysosomes, phagolysosomes, and intermediate filaments evidencing this entity as a morphologic continuum that exhibited modified fibroblastic phenotype and variable proportion of macrophagic differentiation.

Análisis de la incidencia de pubertad precoz central tratada con análogos de hormona liberadora de gonadotrofina. Impacto de la pandemia por COVID-19 / Analysis of the incidence of central precocious puberty treated with gonadotropin-releasing hormone analogs. Impact of the COVID-19 pandemic

Introducción. Desde inicios de la pandemia por coronavirus 2019 (COVID-19), fue comunicado en varios países un incremento de las consultas de niñas con pubertad precoz central idiopática (PPCI), sin que contáramos con datos argentinos. Este aumento estaría vinculado con los cambios en el estilo de vida y los niveles de estrés resultantes del aislamiento que afectó particularmente a la población infantil. Objetivos. 1) Describir la evolución de la incidencia de PPCI con requerimiento de inhibición del eje hipotálamo-hipófiso-gonadal (EHHG) en niñas entre 2010 y 2021 en una cohorte del Área Metropolitana de Buenos Aires. 2) Comparar las características de las niñas, con dicho diagnóstico realizado durante la pandemia, con las de un grupo control. Métodos. Serie de tiempo interrumpida y estudio de casos y controles. Resultados. La incidencia anual fue estable entre 2010 y 2017. Desde 2017 hubo un ascenso anual que promedió el 59,9 % (IC95 % 18,6-115,5) y pareciera haberse acelerado durante la pandemia. Constatamos asociación entre haber desarrollado PPCI y haber requerido tratamiento inhibitorio entre el 01 de junio de 2020 y el 31 de mayo de 2021, y dos variables: edad de menarca materna (OR 0,46; IC95 % 0,28-0,77) y antecedente familiar de PPCI (OR 4,42; IC95 % 1,16-16,86). Conclusión. Evidenciamos desde 2017 un aumento significativo en la incidencia de PPCI con requerimiento de inhibición del EHHG. El incremento en la exposición a diversos desencadenantes ambientales durante la pandemia por COVID-19 podría haber ejercido mayor influencia en las niñas con alguna predisposición genética.

Introduction. Since the onset of the coronavirus disease 2019 (COVID-19) pandemic, consultations of girls with idiopathic central precocious puberty (ICPP) increased in several countries, but there were no data from Argentina. This increase may be related to changes in lifestyle and stress levels resulting from the lockdown, which particularly affected the child population. Objectives. 1) To describe the progression of the incidence of ICPP requiring inhibition of the hypothalamic- pituitary-gonadal (HPG) axis in girls between 2010 and 2021 in a cohort from the Metropolitan Area of Buenos Aires. 2) To compare the characteristics of girls diagnosed with ICPP during the pandemic with those of a control group. Methods. Interrupted time-series and case-control study. Results. The annual incidence remained stable between 2010 and 2017. Since 2017, it increased to an average of 59.9% (95% CI: 18.6­115.5) and appears to have accelerated during the pandemic. We found an association between ICPP and requiring inhibitory treatment between June 1 st, 2020 andMay 31 st, 2021 and 2 variables: maternal age at menarche (OR: 0.46, 95% CI: 0.28­0.77) and family history of ICPP (OR: 4.42, 95% CI: 1.16­16.86). Conclusion. We evidenced a significant increase in the incidence of ICPP with requirement of HPG axis inhibition since 2017. Increased exposure to various environmental triggers during the COVID-19 pandemic may have had a greater influence in girls with some genetic predisposition.

Analysis of the incidence of central precocious puberty treated with gonadotropin-releasing hormone analogs. Impact of the COVID-19 pandemic. / Análisis de la incidencia de pubertad precoz central tratada con análogos de hormona liberadora de gonadotrofina. Impacto de la pandemia por COVID-19.

Introduction. Since the onset of the coronavirus disease 2019 (COVID-19) pandemic, consultations of girls with idiopathic central precocious puberty (ICPP) increased in several countries, but there were no data from Argentina. This increase may be related to changes in lifestyle and stress levels resulting from the lockdown, which particularly affected the child population. Objectives. 1) To describe the progression of the incidence of ICPP requiring inhibition of the hypothalamic-pituitary-gonadal (HPG) axis in girls between 2010 and 2021 in a cohort from the Metropolitan Area of Buenos Aires. 2) To compare the characteristics of girls diagnosed with ICPP during the pandemic with those of a control group. Methods. Interrupted time-series and case-control study. Results. The annual incidence remained stable between 2010 and 2017. Since 2017, it increased to an average of 59.9% (95% CI: 18.6-115.5) and appears to have accelerated during the pandemic. We found an association between ICPP and requiring inhibitory treatment between June 1st, 2020 and May 31st, 2021 and 2 variables: maternal age at menarche (OR: 0.46, 95% CI: 0.28-0.77) and family history of ICPP (OR: 4.42, 95% CI: 1.16-16.86). Conclusion. We evidenced a significant increase in the incidence of ICPP with requirement of HPG axis inhibition since 2017. Increased exposure to various environmental triggers during the COVID-19 pandemic may have had a greater influence in girls with some genetic predisposition.

Introducción. Desde inicios de la pandemia por coronavirus 2019 (COVID-19), fue comunicado en varios países un incremento de las consultas de niñas con pubertad precoz central idiopática (PPCI), sin que contáramos con datos argentinos. Este aumento estaría vinculado con los cambios en el estilo de vida y los niveles de estrés resultantes del aislamiento que afectó particularmente a la población infantil. Objetivos. 1) Describir la evolución de la incidencia de PPCI con requerimiento de inhibición del eje hipotálamo-hipófiso-gonadal (EHHG) en niñas entre 2010 y 2021 en una cohorte del Área Metropolitana de Buenos Aires. 2) Comparar las características de las niñas, con dicho diagnóstico realizado durante la pandemia, con las de un grupo control. Métodos. Serie de tiempo interrumpida y estudio de casos y controles. Resultados. La incidencia anual fue estable entre 2010 y 2017. Desde 2017 hubo un ascenso anual que promedió el 59,9 % (IC95 % 18,6-115,5) y pareciera haberse acelerado durante la pandemia. Constatamos asociación entre haber desarrollado PPCI y haber requerido tratamiento inhibitorio entre el 01 de junio de 2020 y el 31 de mayo de 2021, y dos variables: edad de menarca materna (OR 0,46; IC95 % 0,28-0,77) y antecedente familiar de PPCI (OR 4,42; IC95 % 1,16-16,86). Conclusión. Evidenciamos desde 2017 un aumento significativo en la incidencia de PPCI con requerimiento de inhibición del EHHG. El incremento en la exposición a diversos desencadenantes ambientales durante la pandemia por COVID-19 podría haber ejercido mayor influencia en las niñas con alguna predisposición genética.

Canalización del crecimiento entre los 2 y los 5 años en niños aparentemente sanos con talla baja a los 2 años / Canalization of growth between 2 and 5 years of age in apparently healthy children with short stature at age 2 years

Introducción. El tamaño del recién nacido se asocia a condiciones intrauterinas. El potencial genético se expresa más tarde; la canalización del crecimiento se describe clásicamente hasta los 24 meses. Objetivo. Describir la canalización del crecimiento entre los 2 y los 5 años en niños aparentemente sanos con talla baja a los 2 años. Población y métodos. Estudio de cohorte retrospectiva. Se incluyeron niños seguidos en un hospital universitario de comunidad entre 2003 y 2019, con puntaje Z de talla menor a -2 DE para edad y sexo a los 2 años. Se excluyeron los nacidos prematuros, con bajo peso y con enfermedades crónicas. Se evaluó la trayectoria de crecimiento. Se definió canalización como la adquisición de talla normal para la población general. Resultados. Se incluyeron 64 niños, de los cuales 37 (58 %) presentaron canalización del crecimiento a los 5 años (20 a los 3 años, 8 a los 4 años, y 9 a los 5 años). La velocidad de crecimiento a los 3 y a los 5 años fue significativamente mayor en los que canalizaron en comparación con los que no lo hicieron; hubo una tendencia similar a los 4 años. De los 27 niños con talla baja a los 5 años, 25 tuvieron al menos un registro de velocidad de crecimiento anual menor al percentil 25. Conclusiones. La mayoría de los niños aparentemente sanos con baja talla a los 2 años alcanzan una talla normal a los 5 años. La velocidad de crecimiento anual permite detectar a los niños con riesgo de no canalizar.

Introduction. Newborn size is associated with intrauterine conditions. Genetic potential is expressed later; the canalization of growth is typically described up to 24 months of age. Objective. To describe the canalization of growth between 2 and 5 years of age in apparently healthy children with short stature at age 2 years. Population and methods. Retrospective, cohort study. Children seen at a community teaching hospital between 2003 and 2019, who had a Z-score for height below -2 SDs for age and sex at age 2 years were included. Infants born preterm, with a low birth weight, and chronic conditions were excluded. Growth patterns were assessed. Canalization was defined as reaching a normal stature for the general population. Results. Sixty-four children were included; 37 (58%) showed canalization of growth at 5 years old (20 at 3 years, 8 at 4 years, and 9 at 5 years). The growth rate at 3 and 5 years of age was significantly higher among those who showed canalization compared to those who did not; a similar trend was observed at 4 years of age. Among 27 children with short stature at 5 years of age, 25 had at least 1 annual growth velocity below the 25th centile. Conclusions. Most apparently healthy children with short stature at 2 years old reached a normal stature at 5 years old. The annual growth velocity allows to detect children at risk of not showing canalization.

Blood component requirements in liver transplantation: effect of 2 thromboelastometry-guided strategies for bolus fibrinogen infusion-the TROMBOFIB randomized trial.

BACKGROUND: A low plasma fibrinogen level influences blood component transfusion. Thromboelastometry provides clinical guidance for fibrinogen replacement in liver transplantation (LT). OBJECTIVES: We hypothesized that infusions of fibrinogen concentrate to reach an A10FibTem value of 11 mm during LT could reduce red blood cell (RBC) and other component and fluid requirements in comparison to standard care. METHODS: This randomized, blinded, multicenter trial in 3 hospitals enrolled 189 LT-scheduled patients allocated to an intervention target (A10FibTem, 11 mm) or a standard target (A10FibTem, 8 mm); 176 patients underwent LT with fibrinogen replacement. Data were analyzed by intention-to-treat (intervention group, 91; control group, 85). Blood was extracted, and fibrinogen kits were prepared to bring each patient's fibrinogen level to the assigned target at the start of LT, after portal vein clamping, and after graft reperfusion. The main outcome was the proportion of patients requiring RBC transfusion during LT or within 24 hours. RESULTS: The proportion of patients requiring RBCs did not differ between the groups: intervention, 74.7% (95% CI, 65.5%-83.3%); control, 72.9% (95% CI, 62.2%-82.0%); absolute difference, 1.8% (95% CI, -11.1% to 14.78%) (P = .922). Thrombotic events occurred in 4% of the patients in both groups; reoperation and retransplantation rates and mortality did not differ. Nearly 70% of the patients in both groups required fibrinogen concentrate to reach the target. Using an 11-mm A10FibTem target increased the maximum clot firmness without affecting safety. However, this change provided no clinical benefits. CONCLUSION: The similar low plasma fibrinogen concentrations could explain the lack of significant between-group outcomes.

Gene Promoter-Methylation Signature as Biomarker to Predict Cisplatin-Radiotherapy Sensitivity in Locally Advanced Cervical Cancer.

Despite efforts to promote health policies focused on screening and early detection, cervical cancer continues to be one of the leading causes of mortality in women; in 2020, estimated 30,000 deaths in Latin America were reported for this type of tumor. While the therapies used to treat cervical cancer have excellent results in tumors identified in early stages, those women who are diagnosed in locally advanced and advanced stages show survival rates at 5 years of <50%. Molecular patterns associated with clinical response have been studied in patients who present resistance to treatment; none of them have reached clinical practice. It is therefore necessary to continue analyzing molecular patterns that allow us to identify patients at risk of developing resistance to conventional therapy. In this study, we analyzed the global methylation profile of 22 patients diagnosed with locally advanced cervical cancer and validated the genomic results in an independent cohort of 70 patients. We showed that BRD9 promoter region methylation and CTU1 demethylation were associated with a higher overall survival (p = 0.06) and progression-free survival (p = 0.0001), whereas DOCK8 demethylation was associated with therapy-resistant patients and a lower overall survival and progression-free survival (p = 0.025 and p = 0.0001, respectively). Our results suggest that methylation of promoter regions in specific genes may provide molecular markers associated with response to treatment in cancer; further investigation is needed.

Clinicopathological and immunohistochemical behavior of ductal carcinoma of the salivary and lacrimal gland in a Mexican Mestizo population.

PURPOSE: Salivary gland tumors are rare and include benign and malignant entities with different behavior and prognosis. Salivary gland carcinoma accounts for 0.2% of all cancers and 5-9% of head and neck carcinomas. We aim to describe the clinicopathological characteristics and discuss the immunohistochemical findings of salivary ductal carcinoma. METHODS: We obtained 17 cases (2.3%) of salivary ductal carcinoma (SDC) from 727 patients with parotid tumors at our cancer center from a database covering a 22-year period (1996-2018). Two pathologists confirmed the diagnosis and excluded 6 cases. Eleven cases were assessed by immunohistochemistry (IHC) for HER2, estrogen receptor (ER), progesterone receptor (PR), androgen receptor (AR), mammaglobin, P53, GATA3, S100, cytokeratins (7,8,14,18, and 20), P63, PAX8, calponin, and SOX10. RESULTS: Eleven SDC cases were in advanced stage, and 80% had metastasis. All cases were surgically treated, and 40% received different adjuvant chemotherapy regimens. we found that most patients were dead of disease. The histological and immunohistochemical analysis showed that 70% of cases were high-grade, 40% were positive for HER2, and 50% for AR. Moreover, a high Ki-67 proliferative index was detected in all cases. We observed luminal differentiation in 50% of cases. CONCLUSION: SDC is a rare entity and survival is very poor. It is histologically similar to ductal carcinoma of the breast. However, important differences exist that help to distinguish them in case of synchronous cancers. The clinical behavior of SDC seems to be more aggressive and IHC analysis is useful for designing therapies.

Guidelines for the use and interpretation of assays for monitoring autophagy (4th edition)1.

In 2008, we published the first set of guidelines for standardizing research in autophagy. Since then, this topic has received increasing attention, and many scientists have entered the field. Our knowledge base and relevant new technologies have also been expanding. Thus, it is important to formulate on a regular basis updated guidelines for monitoring autophagy in different organisms. Despite numerous reviews, there continues to be confusion regarding acceptable methods to evaluate autophagy, especially in multicellular eukaryotes. Here, we present a set of guidelines for investigators to select and interpret methods to examine autophagy and related processes, and for reviewers to provide realistic and reasonable critiques of reports that are focused on these processes. These guidelines are not meant to be a dogmatic set of rules, because the appropriateness of any assay largely depends on the question being asked and the system being used. Moreover, no individual assay is perfect for every situation, calling for the use of multiple techniques to properly monitor autophagy in each experimental setting. Finally, several core components of the autophagy machinery have been implicated in distinct autophagic processes (canonical and noncanonical autophagy), implying that genetic approaches to block autophagy should rely on targeting two or more autophagy-related genes that ideally participate in distinct steps of the pathway. Along similar lines, because multiple proteins involved in autophagy also regulate other cellular pathways including apoptosis, not all of them can be used as a specific marker for bona fide autophagic responses. Here, we critically discuss current methods of assessing autophagy and the information they can, or cannot, provide. Our ultimate goal is to encourage intellectual and technical innovation in the field.

Case Report: Uterine Adenosarcoma With Sarcomatous Overgrowth and Malignant Heterologous Elements.

A 46- year-old woman presented a uterine adenosarcoma originating in the lower uterine segment. The diagnosis was made in an endometrial biopsy and confirmed in the pathological examination of the complete surgical specimen, both identifying heterologous malignant elements. In addition, complementary immunohistochemical studies were performed. We reviewed the literature, illustrating the clinical and morphological characteristics and the differential diagnoses to be evaluated.

Pubertad precoz en niñas: potencial impacto de la pandemia y el confinamiento por COVID-19 / Precocious puberty in girls: potential impact of the COVID-19 pandemic and confinement

En este artículo, los autores revisan el concepto de pubertad precoz y los factores que pueden influenciar su desarrollo, en especial en las niñas y en el contexto de las medidas de aislamiento social preventivo y obligatorio durante periodos prolongados a causa de la actual pandemia por el SARS-CoV-2. (AU)

In this article, the authors review the concept of precocious puberty and the factors that may influence its development, especially in girls and in the context of preventive and mandatory social isolation measures for prolonged periods of time due to the current SARS-CoV-2 pandemic. (AU)

Venom alkaloids against Chagas disease parasite: search for effective therapies.

Chagas disease is an important disease affecting millions of patients in the New World and is caused by a protozoan transmitted by haematophagous kissing bugs. It can be treated with drugs during the early acute phase; however, effective therapy against the chronic form of Chagas disease has yet to be discovered and developed. We herein tested the activity of solenopsin alkaloids extracted from two species of fire ants against the protozoan parasite Trypanosoma cruzi, the aetiologic agent of Chagas disease. Although IC50 determinations showed that solenopsins are more toxic to the parasite than benznidazole, the drug of choice for Chagas disease treatment, the ant alkaloids presented a lower selectivity index. As a result of exposure to the alkaloids, the parasites became swollen and rounded in shape, with hypertrophied contractile vacuoles and intense cytoplasmic vacuolization, possibly resulting in osmotic stress; no accumulation of multiple kinetoplasts and/or nuclei was detected. Overexpressing phosphatidylinositol 3-kinase-an enzyme essential for osmoregulation that is a known target of solenopsins in mammalian cells-did not prevent swelling and vacuolization, nor did it counteract the toxic effects of alkaloids on the parasites. Additional experimental results suggested that solenopsins induced a type of autophagic and programmed cell death in T. cruzi. Solenopsins also reduced the intracellular proliferation of T. cruzi amastigotes in infected macrophages in a concentration-dependent manner and demonstrated activity against Trypanosoma brucei rhodesiense bloodstream forms, which is another important aetiological kinetoplastid parasite. The results suggest the potential of solenopsins as novel natural drugs against neglected parasitic diseases caused by kinetoplastids.

Methods to Investigate Signal Transduction Pathways in Trypanosoma cruzi: Cyclic Nucleotide Phosphodiesterases Assay Protocols.

Intracellular levels of cyclic nucleotide second messengers are regulated predominantly by a large superfamily of phosphodiesterases (PDEs). Most of the different PDE variants play specific physiological functions; in fact, PDEs can associate with other proteins allowing them to be strategically anchored throughout the cell. In this regard, precise cellular expression and compartmentalization of these enzymes produce the specific control of cyclic adenosine monophosphate (cAMP) and cyclic guanosine monophosphate (cGMP) gradients in cells and enable their integration with other signaling pathways.In trypanosomatids, some PDEs are essential for their survival and play fundamental roles in the adaptation of these parasites to different environmental stresses, as well as in the differentiation between their different life cycle forms. Given that these enzymes not only are similar to human PDEs but also have differential biochemical properties, and due to the great knowledge of drugs that target human PDEs, trypanosomatid PDEs could be postulated as important therapeutic targets through the repositioning of drugs.In this chapter, we describe a simple and sensitive radioisotope-based method to measure cyclic 3',5'-nucleotide phosphodiesterase using [3H]cAMP.

Intracellular cyclic AMP levels modulate differential adaptive responses on epimastigotes and cell culture trypomastigotes of Trypanosoma cruzi.

Among the many environmental challenges the parasite Trypanosoma cruzi has to overcome to complete its life cycle through different hosts, oxidative stress plays a central role. Different stages of this parasite encounter distinct sources of oxidative stress, such as the oxidative burst of the immune system, or the Heme released from hemoglobin degradation in the triatomine's midgut. Also, the redox status of the surroundings functions as a signal to the parasite, triggering processes coupled to differentiation or proliferation. Intracellular second messengers, like cAMP, are responsible for the transduction of environmental queues and initiating cellular processes accordingly. In trypanosomatids cAMP is involved in a variety of processes, including proliferation, differentiation, osmoregulation and quorum sensing. Trypanosomatid phosphodiesterases (PDE) show atypical pharmacological properties and some have been involved in key processes for the survival of the parasites, which validates them as attractive therapeutic targets. Our work here shows that cAMP modulates different processes according to parasite stage. Epimastigotes become more resistant to oxidative stress when pre-treated with cAMP analogs, while in trypomastigotes an increase in intracellular cAMP doesn't seem to aid in this response, although it does increase the number of amastigotes obtained 48 h after infection, compared to the control group. Also, we show that TcrPDEA1, a functionally enigmatic phosphodiesterase with very high Km, is involved in the epimastigotes response to oxidative stress.

TbVps15 is required for vesicular transport and cytokinesis in Trypanosoma brucei.

The class III phosphatidylinositol 3-kinase (PI3K) Vps34 is an important regulator of key cellular functions, including cell growth, survival, intracellular trafficking, autophagy and nutrient sensing. In yeast, Vps34 is associated with the putative serine/threonine protein kinase Vps15, however, its role in signaling has not been deeply evaluated. Here, we have identified the Vps15 orthologue in Trypanosoma brucei, named TbVps15. Knockdown of TbVps15 expression by interference RNA resulted in inhibition of cell growth and blockage of cytokinesis. Scanning electron microcopy revealed a variety of morphological abnormalities, with enlarged parasites and dividing cells that often exhibited a detached flagellum. Transmission electron microscopy analysis of TbVps15 RNAi cells showed an increase in intracellular vacuoles of the endomembrane system and some cells displayed an enlargement of the flagellar pocket, a common feature of cells defective in endocytosis. Moreover, uptake of dextran, transferrin and Concanavalin A was impaired. Finally, TbVps15 downregulation affected the PI3K activity, supporting the hypothesis that TbVps15 and TbVps34 form a complex as occurs in other organisms. In summary, we propose that TbVps15 has a role in the maintenance of cytokinesis, endocytosis and intracellular trafficking in T. brucei.

Displasia fibrosa ósea / Fibrous dysplasia of bone

La displasia fibrosa ósea es un trastorno no hereditario del desarrollo esquelético caracterizado por una proliferación anormal de fibroblastos y diferenciación deficiente de osteoblastos que conduce a un reemplazo del tejido óseo esponjoso por tejido conectivo fibroso. Es producida por una mutación somática activadora del gen GNAS1 que induce una activación y proliferación de células mesenquimales indiferenciadas con formación de tejido fibroso y trabéculas óseas anómalas. Existen formas monostóticas, poliostóticas y craneofaciales con diversos grados de dolor, deformidades y fracturas óseas, aunque muchos casos son asintomáticos. En ocasiones se producen quistes óseos aneurismáticos, hemorragias, compromisos neurológicos y raramente osteosarcomas. Algunos casos se asocian a síndrome de McCune-Albright, síndrome de Mazabraud y a osteomalacia por hipofosfatemia por pérdida tubular renal inducida por el FGF23 producido por el tejido displásico. Los hallazgos en las radiografías convencionales son característicos, aunque variables y de carácter evolutivo. La gammagrafía ósea es la técnica de imagen con mayor sensibilidad para determinar la extensión de la enfermedad. El diagnóstico diferencial incluye múltiples lesiones óseas de características similares y en raras ocasiones se requiere biopsia ósea o estudio genético para confirmarlo. No existe un consenso unánime acerca del abordaje terapéutico de estos pacientes, razón por la cual es necesario un enfoque multidisciplinario. La conducta puede ser expectante o quirúrgica según el tipo de lesiones y es importante el manejo del dolor y de las endocrinopatías asociadas. La mayor experiencia publicada se refiere al uso de bifosfonatos y, más recientemente, denosumab. Los tratamientos actuales son insuficientes para modificar el curso de la enfermedad y es necesario el desarrollo de nuevas moléculas que actúen específicamente en el gen GNAS1 o sobre las células mesenquimales afectadas. (AU)

Fibrous dysplasia of bone is a noninherited developmental anomaly of bone characterized by abnormal proliferation of fibroblasts and differentiation of osteoblasts that cause a replacement of trabeculous bone by fibrous connective tissue. It is caused by a somatic mutation in the GNAS1 gene, which induces an undifferentiated mesenquimal cells activation and proliferation with formation of fibrous tissue and abnormal osseous trabeculae. There are monostotic, polyostotic and craniofacial variants with different grades of bone pain, deformities and fractures, although many cases remain asymptomatic. Aneurysmal bone cysts, bleeding, neurological compromise and infrequently osteosarcoma are possible complications. Some cases are associated to McCune-Albright syndrome, Mazabraud syndrome or hypophosphatemia and osteomalacia due to to renal tubular loss induced by FGF23 produced by dysplastic tissue. The findings on conventional radiography are characteristic although variable and evlolve with time. Bone scintigraphy is the most sensitive technique to evaluate the extent of disease. Differential diagnosis include several osseous lesions of similar appearance and, in some cases, bone biopsy or genetic testing may be necessary. Today, there is no consensus regarding the therapeutic approach for these patients and it is necessary a multidisciplinary medical team. Watchful waiting or surgical interventions can be indicated, depending on the type of bone lesions. Bone pain and associated endocrinopathies management are very important. Most published experience refers to the use of bisphosphonates and, more recently, denosumab. Current treatments are insufficient to modify the natural curse of the disease and therefore, new molecules with specific action on GNAS1 gene or affected mesenchymal cells are necessary. (AU)

The Phosphatidylinositol 3-kinase Class III Complex Containing TcVps15 and TcVps34 Participates in Autophagy in Trypanosoma cruzi.

Autophagy is a degradative process by which eukaryotic cells digest their own components to provide aminoacids that may function as energy source under nutritional stress conditions. There is experimental evidence for autophagy in parasitic protists belonging to the family Trypanosomatidae. However, few proteins implicated in this process have been characterized so far in these parasites. Moreover, it has been shown that autophagy is involved in Trypanosoma cruzi differentiation and thus might have a role in pathogenicity. Here, we report the cloning and biochemical characterization of TcVps15. In addition, we demonstrate that TcVps15 interact with the PI3K TcVps34 and that both proteins associate with cellular membranes. Under nutritional stress conditions, TcVps15 and TcVps34 modify their subcellular distribution showing a partial co-localization in autophagosomes with TcAtg8.1 and using an active site TcVps15-mutated version (TcVps15-K219D-HA) we demonstrated that this relocalization depends on the TcVps15 catalytic activity. Overexpression of TcVps15-HA and TcVps15-K219D-HA also leads to increased accumulation of monodansylcadaverine (MDC) in autophagic vacuoles under nutritional stress conditions compared to wild-type cells. In addition, the MDC-specific activity shows to be significantly higher in TcVps15-HA overexpressing cells when compared with TcVps15-K219D-HA. Our results reveal for the first time a role of TcVps15 as a key regulator of TcVps34 enzymatic activity and implicate the TcVps15-Vps34 complex in autophagy in T. cruzi, exposing a new key pathway to explore novel chemotherapeutic targets.