Pathogenic RAB34 variants impair primary cilium assembly and cause a novel oral-facial-digital syndrome.

Oral-facial-digital syndromes (OFDS) are a group of clinically and genetically heterogeneous disorders characterized by defects in the development of the face and oral cavity along with digit anomalies. Pathogenic variants in over 20 genes encoding ciliary proteins have been found to cause OFDS through deleterious structural or functional impacts on primary cilia. We identified by exome sequencing bi-allelic missense variants in a novel disease-causing ciliary gene RAB34 in four individuals from three unrelated families. Affected individuals presented a novel form of OFDS (OFDS-RAB34) accompanied by cardiac, cerebral, skeletal and anorectal defects. RAB34 encodes a member of the Rab GTPase superfamily and was recently identified as a key mediator of ciliary membrane formation. Unlike many genes required for cilium assembly, RAB34 acts selectively in cell types that use the intracellular ciliogenesis pathway, in which nascent cilia begin to form in the cytoplasm. We find that the protein products of these pathogenic variants, which are clustered near the RAB34 C-terminus, exhibit a strong loss of function. Although some variants retain the ability to be recruited to the mother centriole, cells expressing mutant RAB34 exhibit a significant defect in cilium assembly. While many Rab proteins have been previously linked to ciliogenesis, our studies establish RAB34 as the first small GTPase involved in OFDS and reveal the distinct clinical manifestations caused by impairment of intracellular ciliogenesis.

Evolutionary and functional analyses of LRP5 in archaic and extant modern humans.

BACKGROUND: The human lineage has undergone a postcranial skeleton gracilization (i.e. lower bone mass and strength relative to body size) compared to other primates and archaic populations such as the Neanderthals. This gracilization has been traditionally explained by differences in the mechanical load that our ancestors exercised. However, there is growing evidence that gracilization could also be genetically influenced. RESULTS: We have analyzed the LRP5 gene, which is known to be associated with high bone mineral density conditions, from an evolutionary and functional point of view. Taking advantage of the published genomes of archaic Homo populations, our results suggest that this gene has a complex evolutionary history both between archaic and living humans and within living human populations. In particular, we identified the presence of different selective pressures in archaics and extant modern humans, as well as evidence of positive selection in the African and South East Asian populations from the 1000 Genomes Project. Furthermore, we observed a very limited evidence of archaic introgression in this gene (only at three haplotypes of East Asian ancestry out of the 1000 Genomes), compatible with a general erasing of the fingerprint of archaic introgression due to functional differences in archaics compared to extant modern humans. In agreement with this hypothesis, we observed private mutations in the archaic genomes that we experimentally validated as putatively increasing bone mineral density. In particular, four of five archaic missense mutations affecting the first ß-propeller of LRP5 displayed enhanced Wnt pathway activation, of which two also displayed reduced negative regulation. CONCLUSIONS: In summary, these data suggest a genetic component contributing to the understanding of skeletal differences between extant modern humans and archaic Homo populations.

Rare predicted deleterious FEZF2 variants are associated with a neurodevelopmental phenotype.

FEZF2 encodes a transcription factor critical to neurodevelopment that regulates other neurodevelopment genes. Rare variants in FEZF2 have previously been suggested to play a role in autism, and cases of 3p14 microdeletions that include FEZF2 share a neurodevelopmental phenotype including mild dysmorphic features and intellectual disability. We identified seven heterozygous predicted deleterious variants in FEZF2 (three frameshifts, one recurrent missense in two independent cases, one nonsense, and one complete gene deletion) in unrelated individuals with neurodevelopmental disorders including developmental delay/intellectual disability, autism, and/or attention-deficit/hyperactivity. Variants were confirmed to be de novo in five of seven cases and paternally inherited from an affected father in one. Predicted deleterious variants in FEZF2 may affect the expression of genes that are involved in fate choice pathways in developing neurons, and thus contribute to the neurodevelopmental phenotype. Future studies are needed to clarify the mechanism by which FEZF2 leads to this neurodevelopmental disorder.

Genetics and Genomics of SOST: Functional Analysis of Variants and Genomic Regulation in Osteoblasts.

SOST encodes the sclerostin protein, which acts as a key extracellular inhibitor of the canonical Wnt pathway in bone, playing a crucial role in skeletal development and bone homeostasis. The objective of this work was to assess the functionality of two variants previously identified (the rare variant rs570754792 and the missense variant p.Val10Ile) and to investigate the physical interactors of the SOST proximal promoter region in bone cells. Through a promoter luciferase reporter assay we show that the minor allele of rs570754792, a variant located in the extended TATA box motif, displays a significant decrease in promoter activity. Likewise, through western blot studies of extracellular and intracellular sclerostin, we observe a reduced expression of the p.Val10Ile mutant protein. Finally, using a circular chromosome conformation capture assay (4C-seq) in 3 bone cell types (MSC, hFOB, Saos-2), we have detected physical interactions between the SOST proximal promoter and the ECR5 enhancer, several additional enhancers located between EVT4 and MEOX1 and a distant region containing exon 18 of DHX8. In conclusion, SOST presents functional regulatory and missense variants that affect its expression and displays physical contacts with far reaching genomic sequences, which may play a role in its regulation within bone cells.

Functional Analyses of Four CYP1A1 Missense Mutations Present in Patients with Atypical Femoral Fractures.

Osteoporosis is the most common metabolic bone disorder and nitrogen-containing bisphosphonates (BP) are a first line treatment for it. Yet, atypical femoral fractures (AFF), a rare adverse effect, may appear after prolonged BP administration. Given the low incidence of AFF, an underlying genetic cause that increases the susceptibility to these fractures is suspected. Previous studies uncovered rare CYP1A1 mutations in osteoporosis patients who suffered AFF after long-term BP treatment. CYP1A1 is involved in drug metabolism and steroid catabolism, making it an interesting candidate. However, a functional validation for the AFF-associated CYP1A1 mutations was lacking. Here we tested the enzymatic activity of four such CYP1A1 variants, by transfecting them into Saos-2 cells. We also tested the effect of commonly used BPs on the enzymatic activity of the CYP1A1 forms. We demonstrated that the p.Arg98Trp and p.Arg136His CYP1A1 variants have a significant negative effect on enzymatic activity. Moreover, all the BP treatments decreased CYP1A1 activity, although no specific interaction with CYP1A1 variants was found. Our results provide functional support to the hypothesis that an additive effect between CYP1A1 heterozygous mutations p.Arg98Trp and p.Arg136His, other rare mutations and long-term BP exposure might generate susceptibility to AFF.

Impact of mechanical circulatory support on survival in pediatric heart transplantation.

Evidence on the impact of MCS on pediatric heart transplant survival is still scarce related to congenital heart disease patients including univentricular physiology as well as the risk factors for complications. We performed a retrospective review of all urgent pediatric (aged ≤16 years) HT from 2004 to 2014 in the Spanish Pediatric Heart Transplant Registry Group. Patients were stratified into two groups: urgent 0 (MCS at HT) and urgent 1 (non-MCS at HT). The primary outcome measure was post-transplant survival; secondary outcome measures were complications and absence of infections and rejection during the first post-transplant year. One hundred twenty-one pediatric patients underwent urgent HT, 58 (47.9%) urgent 0 and 63 (52%) urgent 1. There were 30 (24.8%) deaths: 12 in the urgent 0 group and 18 in the urgent 1 group, P = n.s. Regarding the type of MCS, patients on ECMO had the highest rate of complications (80%) and mortality (40%). Patients in the urgent 1 group showed a higher risk of hospital re-admission for infection during the first year after transplantation (OR 2.31 [1.1-4.82]), P = .025. We did not identify a risk factor for mortality. MCS does not impact negatively on survival after HT. However, there is a significant increase in 30-day and 1-year mortality and complications in ECMO patients compared with VAD patients. Infants, congenital heart disease, and PediMACS were not found to be risk factors for mortality.

Immobilization of BMP-2 and VEGF within Multilayered Polydopamine-Coated Scaffolds and the Resulting Osteogenic and Angiogenic Synergy of Co-Cultured Human Mesenchymal Stem Cells and Human Endothelial Progenitor Cells.

We have previously reported the fabrication of a polycaprolactone and hydroxyapatite composite scaffold incorporating growth factors to be used for bone regeneration. Two growth factors were incorporated employing a multilayered coating based on polydopamine (PDA). In particular, Bone morphogenetic protein-2 (BMP-2) was bound onto the inner PDA layer while vascular endothelial growth factor (VEGF) was immobilized onto the outer one. Herein, the in vitro release of both growth factors is evaluated. A fastest VEGF delivery followed by a slow and more sustained release of BMP-2 was demonstrated, thus fitting the needs for bone tissue engineering applications. Due to the relevance of the crosstalk between bone-promoting and vessel-forming cells during bone healing, the functionalized scaffolds are further assessed on a co-culture setup of human mesenchymal stem cells and human endothelial progenitor cells. Osteogenic and angiogenic gene expression analysis indicates a synergistic effect between the growth factor-loaded scaffolds and the co-culture conditions. Taken together, these results indicate that the developed scaffolds hold great potential as an efficient platform for bone-tissue applications.

Immune dysregulation and Th2 polarization are associated with atopic dermatitis in heart-transplant children: A delicate balance between risk of rejection or atopic symptoms.

Atopic dermatitis (AD) has a high incidence in heart-transplant children, and the reason why there is more AD after transplantation is still unknown. We conducted a cross-sectional study comparing 11 AD and 11 non-AD age-matched heart-transplant children, to assess which immune alterations are related to AD in these patients. AD patients had been transplanted at a younger age compared to non-AD, indicating that age at transplant may be determinant in the onset of AD. The earlier thymectomy in AD heart-transplant children favored the presence of more differentiated phenotypes in the T cell compartment. We observed a clear reduction in the T-helper 1/T-helper 2 (Th1/Th2) ratio in AD children. This Th2 polarization was related to eosinophilia and high immunoglobulin E levels, but also to an impaired regulatory T cell (Treg) suppression, which could be secondary to an exhaustion of the Treg compartment. Interestingly, AD patients were free of rejection episodes (0/11) in comparison to non-AD children (4/11). We propose that a predominant Th2 phenotype may prevent the emergence of Th1 responses associated with graft rejection. A more differentiated Treg phenotype could also play a role in preventing acute rejection in the first year posttransplant. Our findings provide useful insights and knowledge for the better understanding of atopic disorders in transplanted children.

Long-term treatment persistence and maintained reduction of LDL-cholesterol levels with evolocumab over 30 months: Results from the Spanish cohort of the European prospective HEYMANS study.

AIMS: Limited data exist on low-density lipoprotein-cholesterol (LDL-C) level variability or long-term persistence with the monoclonal antibody evolocumab in routine clinical practice. HEYMANS (NCT02770131) is the first multi-country, multicenter, observational study of European patients initiating evolocumab as part of their routine clinical management, based on local reimbursement criteria (overall data recently published). The aim of this analysis is to describe clinical characteristics, baseline and changes in LDL-C levels, treatment patterns and persistence to evolocumab over 30 months in the Spanish cohort using data from the HEYMANS Registry. METHODS: HEYMANS was a prospective study of adult patients (≥18 years) who received at least one dose of evolocumab. A total of 1951 patients were enrolled from 12 countries and were followed up for 30 months after evolocumab initiation. Data were collected for 6 months before evolocumab initiation and up to 30 months thereafter. The Spanish cohort included patients who started evolocumab in routine clinical practice from March 2016 to September 2019. Demographic and clinical characteristics, lipid-lowering therapies (LLT), and lipid levels were collected. RESULTS: In total, 201 patients were included in the Spanish cohort. Median follow-up (Q1-Q3) was 30.0 (12-30) months. A total of 61.7% of patients were men and the mean (standard deviation) age was 59.5 (10.8) years. Most patients (68.7%) had experienced a prior cardiovascular event, 45.3% had coronary artery disease or stable angina, and 60.2% had a diagnosis of familial hypercholesterolemia. Overall, 57.7% of patients were receiving treatment with statins, most of them with high-intensity statins (85.3%); 45.8% of patients were intolerant to statins, and 26.4% of patients did not receive any LLT. At baseline, median (Q1-Q3) LDL-C levels were 151 (123-197) mg/dL. After 3 months of treatment, baseline LDL-C decreased by 66% to a median of 50 (30-83) mg/dL and these levels were maintained over time, with a median LDL-C of 55 (40-99) mg/dL at 30 months. At months 10-12 of treatment, LDL-C levels<55mg/dL were achieved by 56.3% of patients. LDL-C levels<70mg/dL were achieved by 70.1% of patients, and a lowering of LDL-C levels ≥50% was achieved by 76.8% of patients. The percentage of patients on evolocumab treatment was 95% at 12 months and 93% at 30 months. CONCLUSIONS: In the Spanish cohort in routine clinical practice, evolocumab therapy provided a reduction in LDL-C levels consistent with that reported in previous clinical trials, which was sustained during 30 months of follow-up. Treatment with evolocumab was started at LDL-C levels 50% higher than those recommended by The Spanish Society of Arteriosclerosis and the Therapeutic Positioning Report. The probability of achieving the 2019 ESC/EAS LDL-C goals would improve with combination therapy and also with a lower LDL-C threshold when starting evolocumab. Persistence to evolocumab remained high during follow-up, with a very low percentage of discontinuation (5% at 12 months; 7% at 30 months).

Impact of physician's perception about LDL cholesterol control in clinical practice when treating patients in Spain.

BACKGROUND AND AIMS: We aimed to understand the impact of physicians' perception about LDL-cholesterol (LDLc) control on the management of patients with dyslipidemia in Spain. METHODS: We performed a cross-sectional and multicenter study, in which 435 healthcare professionals participated in face-to-face meetings, collecting qualitative and quantitative information related to hypercholesterolemia management. Additionally, aggregated anonymized data of the last 10 patients with hypercholesterolemia attended by each physician were collected. RESULTS: A total of 4,010 patients (8%, 13%, 16% and 61% with low, moderate, high, and very high cardiovascular [CV] risk) were included. Physicians' perception was that 62% of their patients attained LDLc goals (66%, 63%, 61% and 56%, for low, moderate, high and very high CV risk, respectively). However, when looking into the data only 31% (vs 62% p<0.01) of patients attained the LDLc goals (47%, 36%, 22% and 25%, respectively). Overall, 33% of patients were taking high intensity statins, 32% statin/ezetimibe, 21% low/moderate intensity statins and 4% PCSK9 inhibitors. These numbers were 38%, 45%, 8% and 6% for very high risk patients and 44%, 21%, 21% and 4% for high CV risk patients. In 32% of patients, a change in lipid lowering therapy was performed after the visit, mainly combining statins/ezetimibe (55%). CONCLUSIONS: In Spain, most patients with dyslipidemia do not achieve the recommended LDLc goals because of an insufficient intensification of lipid lowering therapy. On the one hand, this is in part due to physicians misperception on preventive LDLc control and the need for repeated advice to patient, and, on the other, to the lack of patient adherence.

First-in-human therapy with Treg produced from thymic tissue (thyTreg) in a heart transplant infant.

Due to their suppressive capacity, regulatory T cells (Tregs) have attracted growing interest as an adoptive cellular therapy for the prevention of allograft rejection, but limited Treg recovery and lower quality of adult-derived Tregs could represent an obstacle to success. To address this challenge, we developed a new approach that provides large quantities of Tregs with high purity and excellent features, sourced from thymic tissue routinely removed during pediatric cardiac surgeries (thyTregs). We report on a 2-year follow-up of the first patient treated worldwide with thyTregs, included in a phase I/II clinical trial evaluating the administration of autologous thyTreg in infants undergoing heart transplantation. In addition to observing no adverse effects that could be attributed to thyTreg administration, we report that the Treg frequency in the periphery was preserved during the 2-year follow-up period. These initial results are consistent with the trial objective, which is to confirm safety of the autologous thyTreg administration and its capacity to restore the Treg pool.

Wnt Pathway Extracellular Components and Their Essential Roles in Bone Homeostasis.

The Wnt pathway is involved in several processes essential for bone development and homeostasis. For proper functioning, the Wnt pathway is tightly regulated by numerous extracellular elements that act by both activating and inhibiting the pathway at different moments. This review aims to describe, summarize and update the findings regarding the extracellular modulators of the Wnt pathway, including co-receptors, ligands and inhibitors, in relation to bone homeostasis, with an emphasis on the animal models generated, the diseases associated with each gene and the bone processes in which each member is involved. The precise knowledge of all these elements will help us to identify possible targets that can be used as a therapeutic target for the treatment of bone diseases such as osteoporosis.

Dyslipidemia observatory: Treatment of hypercholesterolemia in Spain, context and levers for improvement in clinical practice. / Protocolo del observatorio de las dislipemias: Tratamiento de la hipercolesterolemia en España, contexto e identificación de medidas de mejora en práctica clínica habitual.

INTRODUCTION AND OBJECTIVES: The treatment of dyslipidemia exhibits wide variability in clinical practice and important limitations that make lipid-lowering goals more difficult to attain. Getting to know the management of these patients in clinical practice is key to understand the existing barriers and to define actions that contribute to achieving the therapeutic goals from the most recent Clinical Practice Guidelines. METHODS: Observatory where the information gathered is based on routine clinical practice and the experience from the healthcare professionals involved in the treatment of dyslipidemia in Spain. The information is collected by health area through: (i) face-to-face meeting with three different medical specialties and (ii) quantitative information related to hypercholesterolemia patients' management (ad-hoc questionnaire). Information includes patients' profiles, assistance burden, guidelines and protocols used, goal attainment, limitations and opportunities in clinical practice. RESULTS: 145 health areas are planned to be included, with the participation of up to 435 healthcare professionals from the 17 Autonomous Regions of Spain. Information collection will result in aggregated data from over four thousand patients. CONCLUSIONS: This observatory aims to understand how hypercholesterolemia is being treated in routine clinical practice in Spain. Even though the preliminary results show important improvement areas in the treatment of dyslipidemias, mechanisms to drive a change towards health outcomes optimization are also identified.

Genetic Analysis in a Familial Case With High Bone Mineral Density Suggests Additive Effects at Two Loci.

Osteoporosis is the most common bone disease, characterized by a low bone mineral density (BMD) and increased risk of fracture. At the other end of the BMD spectrum, some individuals present strong, fracture-resistant, bones. Both osteoporosis and high BMD are heritable and their genetic architecture encompasses polygenic inheritance of common variants and some cases of monogenic highly penetrant variants in causal genes. We have investigated the genetics of high BMD in a family segregating this trait in an apparently Mendelian dominant pattern. We searched for rare causal variants by whole-exome sequencing in three affected and three nonaffected family members. Using this approach, we have identified 38 rare coding variants present in the proband and absent in the three individuals with normal BMD. Although we have found four variants shared by the three affected members of the family, we have not been able to relate any of these to the high-BMD phenotype. In contrast, we have identified missense variants in two genes, VAV3 and ADGRE5, each shared by two of out of three affected members, whose loss of function fits with the phenotype of the family. In particular, the proband, a woman displaying the highest BMD (sum Z-score = 7), carries both variants, whereas the other two affected members carry one each. VAV3 encodes a guanine-nucleotide-exchange factor with an important role in osteoclast activation and function. Although no previous cases of VAV3 mutations have been reported in humans, Vav3 knockout (KO) mice display dense bones, similarly to the high-BMD phenotype present in our family. The ADGRE5 gene encodes an adhesion G protein-coupled receptor expressed in osteoclasts whose KO mouse displays increased trabecular bone volume. Combined, these mouse and human data highlight VAV3 and ADGRE5 as novel putative high-BMD genes with additive effects, and potential therapeutic targets for osteoporosis. © 2022 The Authors. JBMR Plus published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research.

Clinical description and genetic analysis of a novel familial skeletal dysplasia characterized by high bone mass and lucent bone lesions.

High bone mass (HBM) disorders are a clinically and genetically heterogeneous subgroup of rare skeletal dysplasias. Here we present a case of a previously unreported familial skeletal dysplasia characterized by HBM and lucent bone lesions that we aimed to clinically characterize and genetically investigate. For phenotyping, we reviewed past clinical records and imaging tests, and performed physical examination (PE), bone densitometry, and mineral panels in affected individuals, including a male proband, his son and daughter, in addition to unaffected controls, including the proband's wife and brother. Affected individuals also underwent impact microindentation (IMI). In an effort to elucidate the disorder's molecular etiology, whole exome sequencing (WES) was performed in all individuals to filter for rare variants present only in affected ones. The cases displayed a unique skeletal phenotype with a mix of sclerotic features and lucent bone lesions, and high IMI values. Bone mineral density was very elevated in the proband and his daughter. The proband's daughter also exhibited idiopathic scoliosis (IS), in addition to mild thrombocytopenia and mild structural thyroid abnormalities, which were the only extra-skeletal abnormalities identified. WES analysis yielded 5 rare putative pathogenic variants in affected members in genes that are associated with bone metabolism including: SEM4AD, TBX18, PTCH1, PTK7, and ADGRE5. The PTK7 variant appeared as possibly implicated in the development of IS while the TBX18 and SEMA4D variants stood out as the strongest candidates for the lucent bone lesions and HBM, respectively, given their high predicted pathogenicity and putative role in bone biology. Variant functionality should be addressed in the future to assess their implication in skeletal metabolism as it is the first time that mutations in TBX18 and SEMA4D have been associated to bone developmental lesions and mineral metabolism in a clinical setting.

On the association between Chiari malformation type 1, bone mineral density and bone related genes.

Background: Chiari malformation type 1 (C1M) is a neurological disease characterized by herniation of the cerebellar tonsils below the foramen magnum. Cranial bone constriction is suspected to be its main cause. To date, genes related to bone development (e.g. DKK1 or COL1A2) have been associated with C1M, while some bone diseases (e.g. Paget) have been found to cosegregate with C1M. Nevertheless, the association between bone mineral density (BMD) and C1M has not been investigated, yet. Here, we systematically investigate the association between C1M and BMD, and between bone related genes and C1M. Methods: We have recruited a small cohort of C1M patients (12 unrelated patients) in whom we have performed targeted sequencing of an in-house bone-related gene panel and BMD determination through non-invasive DXA. Results: In the search for association between the bone related genes and C1M we have found variants in more than one C1M patient in WNT16, CRTAP, MYO7A and NOTCH2. These genes have been either associated with craniofacial development in different ways, or previously associated with C1M (MYO7A). Regarding the potential link between BMD and C1M, we have found three osteoporotic patients and one patient who had high BMD, very close to the HBM phenotype values, although most patients had normal BMD. Conclusions: Variants in bone related genes have been repeatedly found in some C1M cases. The relationship of bone genes with C1M deserves further study, to get a clearer estimate of their contribution to its etiology. No direct correlation between BMD and C1M was observed.

A Novel GMP Protocol to Produce High-Quality Treg Cells From the Pediatric Thymic Tissue to Be Employed as Cellular Therapy.

Due to their suppressive capacity, the adoptive transfer of regulatory T cells (Treg) has acquired a growing interest in controlling exacerbated inflammatory responses. Limited Treg recovery and reduced quality remain the main obstacles in most current protocols where differentiated Treg are obtained from adult peripheral blood. An alternate Treg source is umbilical cord blood, a promising source of Treg cells due to the higher frequency of naïve Treg and lower frequency of memory T cells present in the fetus' blood. However, the Treg number isolated from cord blood remains limiting. Human thymuses routinely discarded during pediatric cardiac surgeries to access the retrosternal operative field has been recently proposed as a novel source of Treg for cellular therapy. This strategy overcomes the main limitations of current Treg sources, allowing the obtention of very high numbers of undifferentiated Treg. We have developed a novel good manufacturing practice (GMP) protocol to obtain large Treg amounts, with very high purity and suppressive capacity, from the pediatric thymus (named hereafter thyTreg). The total amount of thyTreg obtained at the end of the procedure, after a short-term culture of 7 days, reach an average of 1,757 x106 (range 50 x 106 - 13,649 x 106) cells from a single thymus. The thyTreg product obtained with our protocol shows very high viability (mean 93.25%; range 83.35% - 97.97%), very high purity (mean 92.89%; range 70.10% - 98.41% of CD25+FOXP3+ cells), stability under proinflammatory conditions and a very high suppressive capacity (inhibiting in more than 75% the proliferation of activated CD4+ and CD8+ T cells in vitro at a thyTreg:responder cells ratio of 1:1). Our thyTreg product has been approved by the Spanish Drug Agency (AEMPS) to be administered as cell therapy. We are recruiting patients in the first-in-human phase I/II clinical trial worldwide that evaluates the safety, feasibility, and efficacy of autologous thyTreg administration in children undergoing heart transplantation (NCT04924491). The high quality and amount of thyTreg and the differential features of the final product obtained with our protocol allow preparing hundreds of doses from a single thymus with improved therapeutic properties, which can be cryopreserved and could open the possibility of an "off-the-shelf" allogeneic use in another individual.

Gene Network of Susceptibility to Atypical Femoral Fractures Related to Bisphosphonate Treatment.

Atypical femoral fractures (AFF) are rare fragility fractures in the subtrocantheric or diaphysis femoral region associated with long-term bisphosphonate (BP) treatment. The etiology of AFF is still unclear even though a genetic basis is suggested. We performed whole exome sequencing (WES) analysis of 12 patients receiving BPs for at least 5 years who sustained AFFs and 4 controls, also long-term treated with BPs but without any fracture. After filtration and prioritization of rare variants predicted to be damaging and present in genes shared among at least two patients, a total of 272 variants in 132 genes were identified. Twelve of these genes were known to be involved in bone metabolism and/or AFF, highlighting DAAM2 and LRP5, both involved in the Wnt pathway, as the most representative. Afterwards, we intersected all mutated genes with a list of 34 genes obtained from a previous study of three sisters with BP-related AFF, identifying nine genes. One of these (MEX3D) harbored damaging variants in two AFF patients from the present study and one shared among the three sisters. Gene interaction analysis using the AFFNET web suggested a complex network among bone-related genes as well as with other mutated genes. BinGO biological function analysis highlighted cytoskeleton and cilium organization. In conclusion, several genes and their interactions could provide genetic susceptibility to AFF, that along with BPs treatment and in some cases with glucocorticoids may trigger this so feared complication.

Mass spectrometric detection of cholesterol oxidation in bovine sperm.

We report on the presence and formation of cholesterol oxidation products (oxysterols) in bovine sperm. Although cholesterol is the most abundant molecule in the membrane of mammalian cells and is easily oxidized, this is the first report on cholesterol oxidation in sperm membranes as investigated by state-of-the-art liquid chromatographic and mass spectrometric methods. First, oxysterols are already present in fresh semen samples, showing that lipid peroxidation is part of normal sperm physiology. After chromatographic separation (by high-performance liquid chromatography), the detected oxysterol species were identified with atmospheric pressure chemical ionization mass spectrometry in multiple-reaction-monitoring mode that enabled detection in a broad and linear concentration range (0.05-100 pmol for each oxysterol species detected). Second, exposure of living sperm cells to oxidative stress does not result in the same level and composition of oxysterol species compared with oxidative stress imposed on reconstituted vesicles from protein-free sperm lipid extracts. This suggests that living sperm cells protect themselves against elevated oxysterol formation. Third, sperm capacitation induces the formation of oxysterols, and these formed oxysterols are almost completely depleted from the sperm surface by albumin. Fourth, and most importantly, capacitation after freezing/thawing of sperm fails to induce both the formation of oxysterols and the subsequent albumin-dependent depletion of oxysterols from the sperm surface. The possible physiological relevance of capacitation-dependent oxysterol formation and depletion at the sperm surface as well as the omission of this after freezing/thawing semen is discussed.