Cranio-cervical abnormalities in moderate-to-severe osteogenesis imperfecta - Genotypic and phenotypic determinants.

INTRODUCTION: Cranio-cervical anomalies are significant complications of osteogenesis imperfecta (OI), a rare bone fragility disorder that is usually caused by mutations in collagen type I encoding genes. OBJECTIVE: To assess cranio-cervical anomalies and associated clinical findings in patients with moderate-to-severe OI using 3D cone beam computed tomography (CBCT) scans. METHODS: Cross-sectional analysis of CBCT scans in 52 individuals with OI (age 10-37 years; 32 females) and 40 healthy controls (age 10-32 years; 26 females). Individuals with a diagnosis of OI type III (severe, n = 11), type IV (moderate, n = 33) and non-collagen OI (n = 8) were recruited through the Brittle Bone Disorders Consortium. Controls were recruited through the orthodontic clinic of the University of Missouri-Kansas City (UMKC). RESULTS: OI and control groups were similar in mean age (OI: 18.4 [SD: 7.2] years, controls: 18.1 [SD: 6.3] years). The cranial base angle was increased in the OI group (OI: mean 148.6° [SD: 19.3], controls: mean 130.4° [SD: 5.7], P = .001), indicating a flatter cranial base. Protrusion of the odontoid process into the foramen magnum (n = 7, 14%) and abnormally located odontoid process (n = 19, 37%) were observed in the OI group but not in controls. Low stature, expressed as height z-score (P = .01), presence of DI (P = .04) and being male (P = .04) were strong predictors of platybasia, whereas height z-score (P = .049) alone was found as positive predictor for basilar impression as per the Chamberlain measurement. CONCLUSION: The severity of the phenotype in OI, as expressed by the height z-score, correlates with the severity of cranial base anomalies such as platybasia and basilar impression in moderate-to-severe OI. Screening for cranial base anomalies is advisable in individuals with moderate-to-severe OI, with special regards to the individuals with a shorter stature and DI.

Effect of sclerostin inactivation in a mouse model of severe dominant osteogenesis imperfecta.

Osteogenesis imperfecta (OI) is a rare bone disease that is associated with fractures and low bone mass. Sclerostin inhibition is being evaluated as a potential approach to increase bone mass in OI. We had previously found that in Col1a1Jrt/+ mice, a model of severe OI, treatment with an anti-sclerostin antibody had a minor effect on the skeletal phenotype. In the present study, we assessed the effect of genetic sclerostin inactivation in the Col1a1Jrt/+ mouse. We crossed Col1a1Jrt/+ mice with Sost knockout mice to generate Sost-deficient Col1a1Jrt/+ mice and assessed differences between Col1a1Jrt/+ mice with homozygous Sost deficiency and Col1a1Jrt/+ mice with heterozygous Sost deficiency. We found that Col1a1Jrt/+ mice with homozygous Sost deficiency had higher body mass, femur length, trabecular bone volume, cortical thickness and periosteal diameter as well as increased biomechanical parameters of bone strength. Differences between genotypes were larger at the age of 14 weeks than at 8 weeks of age. Transcriptome analysis of RNA extracted from the tibial diaphysis revealed only 5 differentially regulated genes. Thus, genetic inactivation of Sost increased bone mass and strength in the Col1a1Jrt/+ mouse. It appears from these observations that the degree of Sost suppression that is required for eliciting a beneficial response can vary with the genetic cause of OI.

Craniofacial and dental phenotype of two girls with osteogenesis imperfecta due to mutations in CRTAP.

Mutations in CRTAP lead to an extremely rare form of recessive osteogenesis imperfecta (OI). CRTAP deficient mice have a brachycephalic skull, fusion of facial bones, midface retrusion and class III dental malocclusion, but in humans, the craniofacial and dental phenotype has not been reported in detail. Here, we describe craniofacial and dental findings in two 11-year-old girls with biallelic CRTAP mutations. Patient 1 has a homozygous c.472-1021C>G variant in CRTAP intron 1 and a moderately severe OI phenotype. The variant is known to create a cryptic splice site, leading to a frameshift and nonsense-mediated RNA decay. Patient 1 started intravenous bisphosphonate treatment at 2 years of age. At age 11 years, height Z-score was +0.6. She had a short and wide face, concave profile and class III malocclusion, with a prognathic mandible and an antero-posterior crossbite. A panoramic radiograph showed a poor angulation of the second upper right premolar, and no dentinogenesis imperfecta or dental agenesis. Cone-beam computed tomography confirmed these findings and did not reveal any other abnormalities. Patient 2 has a homozygous CRTAP deletion of two amino acids (c.804_809del, p.Glu269_Val270del) and a severe OI phenotype. As previously established, the variant leads to instability of CRTAP protein. Intravenous bisphosphonate treatment was started at the age of 15 months. At 11 years of age her height Z-score was -9.7. She had a long and narrow face and convex profile, maxillary retrusion leading to a class III malocclusion, an edge-to-edge overjet and lateral open bite. Panoramic radiographs showed no dental abnormalities. Cone-beam computed tomography showed occipital bossing, platybasia and wormian bones. In these two girls with CRTAP mutations, the severity of the skeletal phenotype was mirrored in the severity of the craniofacial phenotype. Class III malocclusion and antero-posterior crossbite were a common trait, while dental agenesis or dentinogenesis imperfecta were not detected.

Impact of immunoprophylaxis with palivizumab on respiratory syncytial virus infection in preterm infants less than 35 weeks in Colombian hospitals.

OBJECTIVE: To evaluate the impact of immunoprophylaxis with palivizumab in preterm infants less than 35 weeks in terms of hospitalization rate, intensive care unit requirement, and mortality. METHODS: A prospective cohort study was conducted at six Colombian hospitals. Preterm infants less than 35 weeks who received at least one dose of palivizumab during the first 6 months of life were included. The primary outcome was the hospitalization rate related to respiratory syncytial virus (RSV) infection. RESULTS: A total of 222 newborns participated in the study; 204 (91.8%) completed the 6-month follow-up, and three died during the study. 88.7% received a second dose of palivizumab, 79.7% a third, 34.7% a fourth, and 25.2% a fifth. The nonadjusted incidence rate of RSV infection was 2.4%, and the overall RSV-positive hospitalization rate was 1.9%. The proportion of patients that required Neonatal Intensive Care Unit (NICU) and mechanical ventilation in relation to RSV infection was 1.4%. Discharge with home oxygen, pulmonary dysplasia, and being younger than 6 months were significantly associated with respiratory infection. Furthermore, exposition to cigarette smoke was the only factor associated with increased risk of hospitalization. The group that required hospitalization received fewer doses of palivizumab (p = 0.049). No discontinuation of treatment due to adverse events were reported. No death was judged to be related to palivizumab. CONCLUSION: The hospitalization rate and the need for NICU admission were lower than those reported in the literature. In this real-life setting, palivizumab appears to be effective in preventing serious cases of RSV infection.

Skeletal Effects of Bone-Targeted TGFbeta Inhibition in a Mouse Model of Duchenne Muscular Dystrophy.

Duchenne muscular dystrophy (DMD) is a severe progressive muscle disease that is frequently associated with secondary osteoporosis. Previous studies have shown that TGFbeta inactivating antibody improves the muscle phenotype in mdx mice, a model of DMD. In the present study, we assessed the skeletal effects of treatment with a bone-targeted TGFbeta antibody (PCT-011) in mdx mice. Micro-computed tomography showed that 8 weeks of intraperitoneal administration of PCT-011 (10 mg per kg body mass, 3 times per week) was associated with more than twofold higher trabecular bone volume at the distal femur, which was explained by a higher trabecular number. At the femoral midshaft, PCT-011 exposure increased cortical thickness but did not significantly affect the results of three-point bending tests. Histomorphometric analyses of the lumbar vertebra 4 showed that PCT-011 treatment led to a lower bone formation rate. In conclusion, treatment with the TGFbeta antibody PCT-011 had a positive effect on bone development in mdx mice. Inhibiting TGFbeta activity thus appears to be a promising approach to treat bone fragility in the context of DMD.

Calvaria Bone Transcriptome in Mouse Models of Osteogenesis Imperfecta.

Osteogenesis imperfecta (OI) is a bone fragility disorder that is usually caused by mutations affecting collagen type I. We compared the calvaria bone tissue transcriptome of male 10-week-old heterozygous Jrt (Col1a1 mutation) and homozygous oim mice (Col1a2 mutation) to their respective littermate results. We found that Jrt and oim mice shared 185 differentially expressed genes (upregulated: 106 genes; downregulated: 79 genes). A total of seven genes were upregulated by a factor of two or more in both mouse models (Cyp2e1, Slc13a5, Cgref1, Smpd3, Ifitm5, Cthrc1 and Rerg). One gene (Gypa, coding for a blood group antigen) was downregulated by a factor of two or more in both OI mouse models. Overrepresentation analyses revealed that genes involved in 'ossification' were significantly overrepresented among upregulated genes in both Jrt and oim mice, whereas hematopoietic genes were downregulated. Several genes involved in Wnt signaling and transforming growth factor beta signaling were upregulated in oim mice, but less so in Jrt mice. Thus, this study identified a set of genes that are dysregulated across various OI mouse models and are likely to play an important role in the pathophysiology of this disorder.

Acoustic behaviour of bottlenose dolphins under human care while performing synchronous aerial jumps.

Synchronous behaviours occur when two or more animals display the same behaviour at the same time. However, the mechanisms underlying this synchrony are not well understood. In this study, we carried out an experiment to determine whether or not Bottlenose dolphins use acoustic cues when performing a known synchronised exercise. For this, we recorded three dolphins while they performed requested aerial jumps both individually or synchronously in pairs, with a hydrophone array and a 360° underwater video camera allowing the identification of the subject emitting vocalisations. Results indicated that in pairs, dolphins synchronised their jumps 100% of the time. Whether they jumped alone or in pairs, they produced click trains before and after 92% of jumps. No whistles or burst-pulsed sounds were emitted by the animals during the exercise. The acoustic localisation process allowed the successful identification of the vocalising subject in 19.8% of all cases (N = 141). Our study showed that in all (n = 28) but one successful localisations, the click trains were produced by the same individual. It is worth noting that this individual was the oldest female of the group. This paper provides evidence suggesting that during synchronous behaviours, dolphins use acoustic cues, and more particularly click trains, to coordinate their movements; possibly by eavesdropping on the clicks or echoes produced by one individual leading the navigation.

Relationship between Dietary Habits, Food Attitudes and Food Security Status among Adults Living within the United States Three Months Post-Mandated Quarantine: A Cross-Sectional Study.

COVID-19 has disrupted the lives of many and may have influenced dietary habits through factors such as food security status and attitudes. The purpose of this study was to identify dietary habits and their associations with food insecurity and attitudes among adults living in the United States within three months post-mandated quarantine. An online cross-sectional study was conducted from April to June 2020. Participants (n = 3133) responded to a 71-item questionnaire regarding demographics (n = 7), health information (n = 5), lifestyle habits (n = 8), dietary habits (n = 37), food attitudes (n = 8), and food security status (n = 6). Frequency counts and percentages were tabulated, and multivariate linear regression was conducted to examine associations using STATA v14 at a statistical significance level of p < 0.05. Results showed that most participants indicated no change in dietary habits (43.6-87.4%), yet participants reported increased consumption of sweets (43.8%) and salty snacks (37.4%). A significant positive association for food attitude scores (1.59, 95% CI 1.48 to 1.70; p < 0.001) and food security scores (1.19, 95% CI 0.93 to 1.45; p < 0.001) on total dietary habit scores was found. Future extensive population studies are recommended to help public health authorities frame actions to alleviate the impact that mandated quarantine has on dietary habits.

Contexts of emission of non-signature whistles in bottlenose dolphins (Tursiops truncatus) under human care.

Bottlenose dolphins are social cetaceans that strongly rely on acoustic communication and signaling. The diversity of sounds emitted by the species has been structurally classified into whistles, clicks and burst-pulsed sounds. Although click sounds and individually-specific signature whistles have been largely studied, not much is known about non-signature whistles. Most studies that link behavior and whistle production conduct aerial behavioral observations and link the production of whistles to the general category of social interactions. The aim of this study was to determine if there was a correlation between the non-signature whistle production and the underwater behaviors of a group of bottlenose dolphins (Tursiops truncatus) under human care, during their free time in the absence of trainers. To do this we made audio-video recordings 15 min before and after 10 training sessions of eight dolphins in Boudewijn Seapark (Belgium). For the behavioral analysis we conducted focal follows on each individual based on six behavioral categories. For the acoustical analysis, carried out at the group level, we used the SIGID method to identify non-signature whistles (N = 661) and we classified them in six categories according to their frequency modulation. The occurrences of the six categories of whistles were highly collinear. Most importantly, non-signature whistle production was positively correlated with the time individuals spent slow swimming alone, and was negatively correlated with the time spent in affiliative body contact. This is the first analysis that links the production of non-signature whistles with particular underwater behaviors in this species.

Disección axilar dirigida: Nuestra experiencia con el uso de suspensión de carbón activado / Target axillary dissection: Our experience with the use of charcoal suspension

Objetivo: Determinar la tasa de identificación intra operatoria por el médico cirujano de los ganglios marcados con suspensión de carbón activado previo a la neoadyuvancia. El objetivo secundario es determinar la concordancia entre los ganglios linfáticos marcados con carbón y aquellos considerados ganglios centinelas. Material y método: Es un estudio retrospectivo desde el año 2016 hasta el año 2020. Se incluyeron 27 pacientes con cáncer de mama en estadios T1 - T3 que realizaron quimioterapia neoadyuvante y con axila con estadio N1 y N2. Los ganglios axilares biopsiados con resultado positivo fueron marcados con suspensión de carbón activado, posteriormente las pacientes realizaron quimioterapia neoadyuvante. Se evaluó la tasa de detección y concordancia del ganglio marcado con el ganglio centinela durante el procedimiento quirúrgico. Resultados: Del total de pacientes en 20 casos se realizó efectivamente la identificación por inspección visual de la suspensión de carbón activado en la cavidad axilar durante la cirugía. La tasa de detección fue del 74%. Del total de 20 pacientes en los cuales se identificó carbón visualmente en el acto quirúrgico, 16 se sometieron a biopsia de ganglio centinela. En 81% de los casos hubo una coincidencia entre el ganglio marcado con carbón y el ganglio centinela. Conclusión: En nuestro trabajo la tasa de detección intraoperatoria de los ganglios marcados con carbón está en concordancia con lo publicado en la literatura. Esto catapulta a este método de marcación como una alternativa factible para realizar una disección axilar dirigida asegurándole al médico cirujano la resección de una ganglio positivo de inicio para su análisis anatomopatológico de respuesta. Hemos comprobado que la marcación con carbón no interfiere con la técnica estándar utilizada para la biopsia de ganglio centinela sino que su uso en conjunto mejora la técnica dignóstica.

Objetive: The aim of this study was to determine the rate of identification of activated charcoal suspension during surgery in positive lymph nodes before neadjuvant chemotherapy. The secondary objetive is to determine the rate of concordance between the marked lymph nodes and the sentinel lymph nodes. Material and method: A retrospective study that goes from the year 2016 - 2020. It includes 27 patients with breast cancer (T1 - T3) and positive lymph nodes (N1 - N2). Patients with biopsy - confirmed nodal metatases were marked with activated charcoal suspension in the sampled node. After this procedure patients underwent neoadjuvant chemotherapy and axillary surgery. The rate of detection and the concordance of the marked lymph node with the sentinel lymph nodes was calculated. Results: Of the 27 patients enrolled in this study in 20, the marked node was detected during surgery. The detection rate was of 74%. Of these 20 patientes, 16 had sentinel node biopsy. There was an 81% rate of concordance between the sentinel lymph node and the tattooed lymph node. Conclusions: In our study, the detection rate of marked lymph node is concordant with the numbers publised by other studies. This shows that axillary lymph node tattooing with activated charcoal suspension is a viable, low cost and precise method when performing targeted axillary dissection. We identified that the tattooing procedure does not affect the standard sentinel node biopsy, in fact, when used together it improves its diagnostic performance.

Carbon sequestration and methane emissions along a microtopographic gradient in a tropical Andean peatland.

Tropical alpine peatlands are among the least studied wetlands types on earth. Their important ecosystem services at local and regional scope are currently threatened by climate and land use changes. Recent studies in these ecosystems suggest their importance to the provision of climate regulation services, prompting a better understanding of the underlying functions and their variability at ecosystem scales. The objective of this study is to determine the variability of methane (CH4) fluxes and carbon (C) sequestration within a tropical alpine peatland in three locations along a microtopographic gradient and its associated plant diversity. These locations accounted for: 1) hummocks, found mostly near the edge of the peat with a water table below the soil surface, 2) lawns, in the transition zone, with a water-table near the soil surface, and 3) hollows, permanently flooded with a water table above the soil surface, composed of small patches of open water intermingled with unconsolidated hummocks that surface the water level. Results indicate that CH4 flux is lowest in the lawns, while C sequestration is highest. Conversely, the hummock and hollow have higher CH4 flux and lower C sequestration. In addition, plant diversity in the lawns is higher than in the hummock and hollow location. Dryer conditions brought by current climate change in the northern Andes are expected to lower the water tables in the peatland. This change is expected to drive a change in CH4 flux and C sequestration at the lawns, currently dominating the peatland, towards values more similar to those measured in the hummocks. This decrease may also represent a change towards the lower plant diversity that characterized the hummock. Such changes will reduce the ratio of C sequestration:CH4 flux signifying the reduction of resilience and increment of vulnerability of the climate-regulating service to further perturbations.

Multidisciplinary Approach to Understand Medial Arterial Calcification.

OBJECTIVE: Vascular calcification significantly increases morbidity in life-threatening diseases, and no treatments are available because of lack of understanding of the underlying molecular mechanism. Here, we study the physicochemical details of mineral nucleation and growth in an animal model that faithfully recapitulates medial arterial calcification in humans, to understand how pathological calcification is initiated on the vascular extracellular matrix. APPROACH AND RESULTS: MGP (matrix Gla protein) is a potent mineralization inhibitor. We study the evolution of medial calcification in MGP-deficient mice over the course of 5 weeks using a combination of material science techniques and find that mineral composition and crystallinity evolve over time and space. We show that calcium is adsorbed first and then amorphous calcium phosphate and octacalcium phosphate forms, which then transform into hydroxyapatite and carbonated apatite. These events are repeated after each nucleation event, providing a snapshot of the overall mineral evolution at each time point analyzed. CONCLUSIONS: Our results show that an interdisciplinary approach combining animal models and materials science can provide insights into the mechanism of vascular calcification and suggest the importance of analyzing mineral phases, rather than just overall mineralization extent, to diagnose and possibly prevent disease development.

In vitro comparison of two titanium dental implant surface treatments: 3M™ESPE™ MDIs versus Ankylos®.

BACKGROUND: An ideal implant should have a surface that is conducive to osseointegration. In vitro cell culture studies using disks made of same materials and surface as of implants may provide useful information on the events occurring at the implant-tissue interface. In the current study, we tested the hypothesis that there is no difference in the proliferation and differentiation capacities of osteoblastic cells when cultured on titanium disks mimicking the surface of 3M™ESPE™ MDIs or standard (Ankylos®) implants. METHODS: Cells were grown on disks made of the same materials and with same surface texture as those of the original implants. Disks were sterilized and coated with 2% gelatin solution prior to the cell culture experiments. C2C12 pluripotent cells treated with 300 ng/ml bone morphogenetic protein 2 BMP-2 and a stably transfected C2C12 cell line expressing BMP2 were used as models for osteogenic cells. The Hoechst 33258-stained nuclei were counted to assay cell proliferation, while alkaline phosphatase (ALPL) immunostaining was performed to investigate osteogenic differentiation. MC3T3-E1 cells were cultured as model osteoblasts. The cells were differentiated and assayed for proliferation and metabolic activities by Hoechst 33258 staining and Alamar blue reduction assays, respectively. Additionally, cultures were stained by calcein to investigate their mineral deposition properties. RESULTS: Electron microscopy showed greater degree of roughness on the MDI surfaces. Nuclear counting showed significantly higher number of C2C12 cells on the MDI surface. Although immunostaining detected higher number of ALPL-positive cells, it was not significant when normalized by cell numbers. The number of MC3T3-E1 cells was also higher on the MDI surface, and accordingly, these cultures showed higher Alamar blue reduction. Finally, calcein staining revealed that the MC3T3-E1 cells grown on MDI surfaces deposited more minerals. CONCLUSIONS: Although both implant surfaces are conducive for osteoblastic cell attachment, proliferation, and extracellular matrix mineralization, cell proliferation is higher on MDI surfaces, which may in turn facilitate osseointegration via increased ECM mineralization.

Matrix Gla protein deficiency impairs nasal septum growth, causing midface hypoplasia.

Genetic and environmental factors may lead to abnormal growth of the orofacial skeleton, affecting the overall structure of the face. In this study, we investigated the craniofacial abnormalities in a mouse model for Keutel syndrome, a rare genetic disease caused by loss-of-function mutations in the matrix Gla protein (MGP) gene. Keutel syndrome patients show diffuse ectopic calcification of cartilaginous tissues and impaired midface development. Our comparative cephalometric analyses of micro-computed tomography images revealed a severe midface hypoplasia in Mgp-/- mice. In vivo reporter studies demonstrated that the Mgp promoter is highly active at the cranial sutures, cranial base synchondroses, and nasal septum. Interestingly, the cranial sutures of the mutant mice showed normal anatomical features. Although we observed a mild increase in mineralization of the spheno-occipital synchondrosis, it did not reduce the relative length of the cranial base in comparison with total skull length. Contrary to this, we found the nasal septum to be abnormally mineralized and shortened in Mgp-/- mice. Transgenic restoration of Mgp expression in chondrocytes fully corrected the craniofacial anomalies caused by MGP deficiency, suggesting a local role for MGP in the developing nasal septum. Although there was no up-regulation of markers for hypertrophic chondrocytes, a TUNEL assay showed a marked increase in apoptotic chondrocytes in the calcified nasal septum. Transmission electron microscopy confirmed unusual mineral deposits in the septal extracellular matrix of the mutant mice. Of note, the systemic reduction of the inorganic phosphate level was sufficient to prevent abnormal mineralization of the nasal septum in Mgp-/-;Hyp compound mutants. Our work provides evidence that modulation of local and systemic factors regulating extracellular matrix mineralization can be possible therapeutic strategies to prevent ectopic cartilage calcification and some forms of congenital craniofacial anomalies in humans.

Modulation of whistle production related to training sessions in bottlenose dolphins (Tursiops truncatus) under human care.

Bottlenose dolphins are highly social cetaceans with an extensive sound production including clicks, burst-pulsed sounds, and whistles. Some whistles, known as signature whistles, are individually specific. These acoustic signatures are commonly described as being emitted in contexts of stress during forced isolation and as group cohesion calls. Interactions between humans and captive dolphins is largely based on positive reinforcement conditioning within several training/feeding sessions per day. Vocal behavior of dolphins during these interactions might vary. To investigate this, we recorded 10 bottlenose dolphins of Parc Asterix dolphinarium (France) before, during and after 10 training sessions for a total duration of 7 hr and 32 min. We detected 3,272 whistles with 2,884 presenting a quality good enough to be categorized. We created a catalog of whistle types by visual categorization verified by five naive judges (Fleiss' Kappa Test). We then applied the SIGID method to identify the signatures whistles present in our recordings. We found 279 whistles belonging to one of the four identified signature whistle types. The remaining 2,605 were classified as non-signature whistles. The non-signature whistles emission rate was higher during and after the training sessions than before. Emission rate of three signature whistles types significantly increased afterwards as compared to before the training sessions. We suggest that dolphins use their signature whistles when they return to their intraspecific social interactions succeeding scheduled and human-organized training sessions. More observations are needed to make conclusions about the function of signature whistles in relation to training sessions. Zoo Biol. 35:495-504, 2016. © 2016 Wiley Periodicals, Inc.

Behavioural evidence of magnetoreception in dolphins: detection of experimental magnetic fields.

Magnetoreception, meaning the perception of magnetic fields, is supposed to play an important role for orientation/navigation in some terrestrial and aquatic species. Although some spatial observations of free-ranging cetaceans' migration routes and stranding sites led to the assumption that cetaceans may be sensitive to the geomagnetic field, experimental evidence is lacking. Here, we tested the spontaneous response of six captive bottlenose dolphins to the presentation of two magnetized and demagnetized controlled devices while they were swimming freely. Dolphins approached the device with shorter latency when it contained a strongly magnetized neodymium block compared to a control demagnetized block that was identical in form and density and therefore undistinguishable with echolocation. We conclude that dolphins are able to discriminate the two stimuli on the basis of their magnetic properties, a prerequisite for magnetoreception-based navigation.

Inducible transient expression of Smpd3 prevents early lethality in fro/fro mice.

Sphingomyelin phosphodiesterase 3 (SMPD3) is a pleiotropic lipid metabolizing enzyme involved in multiple physiological processes. A deletion mutation in the murine Smpd3 gene called fragilitas ossium (fro) leads to severe skeletal abnormalities in the developing fro/fro embryos. Although fro/fro mice can be useful to study many different aspects of SMPD3 functions, their perinatal lethality makes it difficult to generate a sufficient number of mice for controlled studies. In fact, on the C57BL/6 genetic background, none of the fro/fro mice survive beyond the perinatal stage. In this study, we used the "Tet-On" inducible gene expression system to express Smpd3 transiently in fro/fro;ROSA-rtTA;TRE-Smpd3 embryos on the C57BL/6 background. This induced Smpd3 expression corrected all the skeletal abnormalities in these embryos and prevented their early death. However, induction of Smpd3 expression in the adolescent fro/fro;ROSA-rtTA;TRE-Smpd3 mice was not sufficient to correct the defects in trabecular bone mineralization and the impaired growth of the long bones. This novel mouse model will be a useful tool to study SMPD3 biology in vivo.

Mechanisms of vascular calcification and associated diseases.

Mineralization of bone and tooth extracellular matrix (ECM) is a physiologic process, while soft tissue mineralization, also known as ectopic mineralization (calcification), is a pathologic condition. Vascular calcification is common in aging and also in a number of genetic and metabolic disorders. The calcific deposits in arteries complicate the prognosis and increase the morbidity in diseases such as atherosclerosis, diabetes and chronic kidney disease (CKD). To completely understand the pathophysiology of these lifethreatening diseases, it is critical to elucidate the molecular mechanisms underlying vascular calcification. Unveiling these mechanisms will eventually identify new therapeutic targets and also improve the management of the associated complications. In the current review, we discussed the common determinants of ECM mineralization, the mechanism of vascular calcification associated with several human diseases and outlined the most common therapeutic approaches to prevent its progression.

Prevention of arterial calcification corrects the low bone mass phenotype in MGP-deficient mice.

Matrix gla protein (MGP), a potent inhibitor of extracellular matrix (ECM) mineralization, is primarily produced by vascular smooth muscle cells (VSMCs) and chondrocytes. Consistent with its expression profile, MGP deficiency in mice (Mgp-/- mice) results in extensive mineralization of all arteries and cartilaginous ECMs. Interestingly, we observed a progressive loss of body weight in Mgp-/- mice, which becomes apparent by the third week of age. Taking into account the new paradigm linking the metabolic regulators of energy metabolism and body mass to that of bone remodeling, we compared the bone volume in Mgp-/- mice to that of their wild type littermates by micro-CT and bone histomorphometry. We found a decrease of bone volume over tissue volume in Mgp-/- mice caused by an impaired osteoblast function. In culture, early differentiation of Mgp-/- primary osteoblasts was not affected; however there was a significant upregulation of the late osteogenic marker Bglap (osteocalcin). We examined whether the prevention of arterial calcification in Mgp-/- mice could correct the low bone mass phenotype. The bones of two different genetic models: Mgp-/-;SM22-Mgp and Mgp-/-;Eln+/- mice were analyzed. In the former strain, vascular calcification was fully rescued by transgenic overexpression of Mgp in the VSMCs, while in the latter, elastin haploinsufficiency significantly impeded the deposition of minerals in the arterial walls. In both models, the low mass phenotype seen in Mgp-/- mice was rescued. Our data support the hypothesis that the arterial calcification, not MGP deficiency itself, causes the low bone mass phenotype in Mgp-/- mice. Taken together, we provide evidence that arterial calcification affects bone remodeling and pave the way for further mechanistic studies to identify the pathway(s) regulating this process.

Odontología para pacientes autistas / Dentistry for the Autistic Patient

La relación entre enfermedades orales y mala higiene oral ha sido bien establecida en la literatura. Sin embargo, su relación directa con el autismo no ha sido demostrada. A pesar de su discapacidad psicomotora, el paciente autista no está limitado para utilizar los servicios odontológicos, más bien, la falta de conocimiento y entrenamiento de los odontólogos generales para la atención de este grupo de pacientes parece ser el problema. El propósito de este artículo es hacer una revisión detallada de la literatura científica existente encontrada en las principales bases de datos internacionales, con el fin de ofrecerle al odontólogo general y al odontopediatra una herramienta para el entendimiento de la condición autista, los conceptos básicos, generalidades, etiología y una detallada descripción de las condiciones orales y los distintos enfoques de tratamiento odontológico. Se describirán con detalle las técnicas de manejo del comportamiento y técnicas de comunicación necesarias para que el profesional de la salud pueda brindar una atención integral desde el punto de vista clínico y humano, teniendo en cuenta que para lograr mantener la salud y mejorar la calidad de vida de este grupo de pacientes, se requiere un enfoque multidisciplinario, donde el odontólogo es parte fundamental del grupo.

The relationship between oral diseases and poor oral hygiene has been well established, however, there is a lack of direct relation with autism. Despite their psychomotor disabilities, the autistic patient is not limited to use the dental services, in the contrary, the lack of knowledge and training of general practitioners to care for this group of patients seem to be the problem. The purpose of this article consists in a detailed scientific literature review found in the major international databases, to provide to the general dentist and the pediatric dentist a tool for understanding the autistic condition, the basic concepts, overview, etiology, and a detailed description of oral conditions and dental treatment approaches. This article describes in detail the behavior management and communication techniques necessary for the dentist to provide a comprehensive and humanized dental care, taking into account that in order to maintain health and improve quality of life, this patients require a multidisciplinary approach, where the dentist is a fundamental part of the group.