José A. Riancho

Seasonal deficiency of vitamin D in children : A potential target for osteoporosis-preventing strategies?

Peak bone mass attained after skeletal growth is a major determinant of the risk of developing osteoporosis later in life, hence the importance of nutritional factors that contribute to bone mass gain during infancy and adolescence. An adequate supply of vitamin D is essential for normal bone homeostasis. This study was undertaken to determine what the levels are of 25‐hydroxyvitamin D (25(OH)D) that may be considered desirable in children and to assess if normal children maintain these levels throughout the year. Vitamin D metabolites and parathyroid hormone (PTH) serum levels were measured in 21 children in March and October, prior to and after the administration of a daily supplement of 25(OH)D (40 μg for 7 consecutive days). There were inverse correlations between basal 25(OH)D levels and supplementation‐induced changes in serum 1,25(OH)2D (r = 0.57, p < 0.05) and PTH (r = 0.41, p < 0.05). When basal levels of 25(OH)D were below 20 ng/ml, the supplement induced an increase in serum 1,25(OH)2D; with basal 25(OH)D under 10–12 ng/ml, the supplement also decreased serum PTH. The lowest serum level of 25(OH)D in 43 normal children studied in summer was 13 ng/ml. Those results suggested that the lowest limit for desirable levels of 25(OH)D in children was somewhere between 12 and 20 ng/ml. However, 31% of 51 normal children studied in winter had levels below 12 ng/ml, and 80% had levels lower than 20 ng/ml. Those children are likely to have suboptimal bioavailability of vitamin D, which might hamper their achievement of an adequate peak bone mass. Since cutaneous synthesis of vitamin D is rather limited in winter, oral vitamin D supplementation should be considered.

FASCIOLIASIS IN DEVELOPED COUNTRIES : A REVIEW OF CLASSIC AND ABERRANT FORMS OF THE DISEASE

Cases of human infestation by Fasciola hepatica are not uncommon in Spain and other European countries. We report our experience with 20 patients diagnosed from 1982 to 1991 and present a critical review of published cases from western countries. Because F. hepatica has a special tropism for the liver, abdominal pain, hepatomegaly, and constitutional symptoms are among the most common manifestations of acute-stage fascioliasis. However, in the chronic stage, biliary colic and cholangitis are the predominant manifestations. The clinical spectrum of fascioliasis is variable, and patients may present with extrahepatic abnormalities, such as pulmonary infiltrates, pleuropericarditis, meningitis, or lymphadenopathy. Therefore, a high index of suspicion is required to establish a correct diagnosis. Eosinophilia is the most frequent laboratory abnormality. The CT scan has become a useful technique in the diagnostic work-up. A definitive diagnosis may be established by the observation of parasite ova in the feces, but most cases may be diagnosed by serologic methods. Triclabendazole and bithionol are the most effective drugs against F. hepatica. The efficacy of praziquantel is controversial.

Blood levels of cytokines in brain-dead patients: relationship with circulating hormones and acute-phase reactants.

We hypothesized that increased levels of blood cytokines occur in brain-dead patients, and that these cytokines are responsible for some of the endocrine and/or acute-phase reactant abnormalities found in these patients. We measured blood levels of cytokines, hormones, and acute-phase reactants in 18 brain-dead potential organ donors at the moment of establishing the legal diagnosis of brain death and compared them with levels found in a control group. Although interleukin-1 beta (IL-1 beta) and tumor necrosis factor-alpha (TNF-alpha) levels were within the normal range, interleukin-6 (IL-6) levels were clearly above the normal range in all patients (median, 1,444 pg/mL; range, 75 to 11,780). In the brain-dead group, total thyroxine (tT4), free T4 (fT4), triiodothyronine (T3), thyrotropin (TSH), dehydroepiandrosterone sulfate (DHEA-S), testosterone, albumin, Zn, and osteocalcin levels were decreased, T3 resin uptake index (T3 RUI), corticotropin (ACTH), cortisol, 11-deoxycortisol (11-DOC), 17-hydroxyprogesterone (17-OHPr), aldosterone, luteinizing hormone, and follicle-stimulating hormone levels were normal, and reverse T3 (rT3), renin, and C-reactive protein (CRP) levels were increased. Multiple regression analysis demonstrated significant interrelations between IL-6 and T4, T3, testosterone, and CRP. We also studied the evolution of some of these parameters in four patients with severe head injury who finally developed brain death. IL-6 levels on admission to the intensive care unit (ICU) were above the normal limits, as in other patients with cranial trauma, but when the patients developed brain death, there was a pronounced increase in IL-6 levels.(ABSTRACT TRUNCATED AT 250 WORDS)

Insights into the genetic architecture of osteoarthritis from stage 1 of the arcOGEN study

Objectives The genetic aetiology of osteoarthritis has not yet been elucidated. To enable a well-powered genome-wide association study (GWAS) for osteoarthritis, the authors have formed the arcOGEN Consortium, a UK-wide collaborative effort aiming to scan genome-wide over 7500 osteoarthritis cases in a two-stage genome-wide association scan. Here the authors report the findings of the stage 1 interim analysis. Methods The authors have performed a genome-wide association scan for knee and hip osteoarthritis in 3177 cases and 4894 population-based controls from the UK. Replication of promising signals was carried out in silico in five further scans (44 449 individuals), and de novo in 14 534 independent samples, all of European descent. Results None of the association signals the authors identified reach genome-wide levels of statistical significance, therefore stressing the need for corroboration in sample sets of a larger size. Application of analytical approaches to examine the allelic architecture of disease to the stage 1 genome-wide association scan data suggests that osteoarthritis is a highly polygenic disease with multiple risk variants conferring small effects. Conclusions Identifying loci conferring susceptibility to osteoarthritis will require large-scale sample sizes and well-defined phenotypes to minimise heterogeneity.

A GEP-ISFG collaborative study on the optimization of an X-STR decaplex: data on 15 Iberian and Latin American populations

In a collaborative work carried out by the Spanish and Portuguese ISFG Working Group (GEP-ISFG), a polymerase chain reaction multiplex was optimized in order to type ten X-chromosome short tandem repeats (STRs) in a single reaction, including: DXS8378, DXS9902, DXS7132, DXS9898, DXS6809, DXS6789, DXS7133, GATA172D05, GATA31E08, and DXS7423. Using this X-decaplex, each 17 of the participating laboratories typed a population sample of approximately 200 unrelated individuals (100 males and 100 females). In this work, we report the allele frequencies for the ten X-STRs in 15 samples from Argentina (Buenos Aires, Córdoba, Río Negro, Entre Ríos, and Misiones), Brazil (São Paulo, Rio de Janeiro, Paraná, and Mato Grosso do Sul), Colombia (Antioquia), Costa Rica, Portugal (Northern and Central regions), and Spain (Galicia and Cantabria). Gene diversities were calculated for the ten markers in each population and all values were above 56%. The average diversity per locus varied between 66%, for DXS7133, and 82%, for DXS6809. For this set of STRs, a high discrimination power was obtained in all populations, both in males (≥1 in 5 × 105) and females (≥1 in 3 × 109), as well as high mean exclusion chance in father/daughter duos (≥99.953%) and in father/mother/daughter trios (≥99.999%). Genetic distance analysis showed no significant differences between northern and central Portugal or between the two Spanish samples from Galicia and Cantabria. Inside Brazil, significant differences were found between Rio de Janeiro and the other three populations, as well as between São Paulo and Paraná. For the five Argentinean samples, significant distances were only observed when comparing Misiones with Entre Ríos and with Río Negro, the only two samples that do not differ significantly from Costa Rica. Antioquia differed from all other samples, except the one from Río Negro.

Reconstructing the DNA Methylation Maps of the Neandertal and the Denisovan

Methylating the Family Tree DNA sequences show a high level of similarities between humans and ancient hominids but the degree to which there are differences between methylated regions in their genomes that may explain phenotypic differences is unclear. Gokhman et al. (p. 523, published online 17 April) demonstrate that naturally degraded methylated cytosines in ancient DNA are converted to thymines and can be used to reconstruct ancient methylomes. The results suggest differences in methylation in bone tissues between modern humans and ancient hominids in a set of genes important for limb development. Estimates of differentially methylated nucleotides illuminate differences between modern human and ancient hominid bones. Ancient DNA sequencing has recently provided high-coverage archaic human genomes. However, the evolution of epigenetic regulation along the human lineage remains largely unexplored. We reconstructed the full DNA methylation maps of the Neandertal and the Denisovan by harnessing the natural degradation processes of methylated and unmethylated cytosines. Comparing these ancient methylation maps to those of present-day humans, we identified ~2000 differentially methylated regions (DMRs). Particularly, we found substantial methylation changes in the HOXD cluster that may explain anatomical differences between archaic and present-day humans. Additionally, we found that DMRs are significantly more likely to be associated with diseases. This study provides insight into the epigenetic landscape of our closest evolutionary relatives and opens a window to explore the epigenomes of extinct species.

Genome‐wide profiling of bone reveals differentially methylated regions in osteoporosis and osteoarthritis

OBJECTIVE To determine genome-wide methylation profiles of bone from patients with hip osteoarthritis (OA) and those with osteoporotic (OP) hip fractures. METHODS Trabecular bone pieces were obtained from the central part of the femoral head of 27 patients with hip fractures and 26 patients with hip OA. DNA was isolated, and methylation was explored with Illumina methylation arrays. RNA was extracted, pooled, and deep-sequenced to obtain the whole transcriptome. Differentially methylated regions were identified, and connections between genes with differentially methylated regions were explored by pathway and text-mining analyses. RESULTS After quality control, methylation of 23,367 CpG sites (13,463 genes) was analyzed. There was a genome-wide inverse relationship between methylation and gene expression in both patient groups. Comparison of OP and OA bones revealed 241 CpG sites, located in 228 genes, with significant differences in methylation (false discovery rate<0.05). Of them, 217 were less methylated in OP than in OA. The absolute methylation differences were >5% in 128 CpG sites and >10% in 45 CpG sites. The differentially methylated genes were enriched for association with bone traits in the genome-wide association study catalog. Pathway analysis and text-mining analysis with Gene Relationships Across Implicated Loci software revealed enrichment in genes participating in glycoprotein metabolism or cell differentiation, and particularly in the homeobox superfamily of transcription factors. CONCLUSION Genome-wide methylation profiling of bone samples revealed differentially methylated regions in OP and OA. These regions were enriched in genes associated with cell differentiation and skeletal embryogenesis, such as those in the homeobox superfamily, suggesting the existence of a developmental component in the predisposition to these disorders.

Atrial fibrillation as a risk factor for stroke recurrence

BACKGROUND Although atrial fibrillation is a well-known risk factor for ischemic stroke, the extent to which it increases the risk of stroke recurrence, particularly in elderly patients, is less certain. METHODS We performed a retrospective cohort study of 915 patients aged 50 to 94 years who were admitted with an ischemic stroke. The rates of recurrent strokes and recurrent severe strokes were estimated with the Kaplan-Meier method. The effects of atrial fibrillation on stroke risk were analyzed with proportional hazards models. RESULTS Of the 829 patients who survived the initial hospitalization, 163 (20%) had a stroke during follow-up. Of the 203 patients with atrial fibrillation during index hospitalization who were not anticoagulated, 54 (27%) had recurrent strokes, compared with 18% (19/103) among those with atrial fibrillation who were anticoagulated and 17% (90/523) among those without atrial fibrillation. The age-adjusted hazard ratio for recurrent stroke among those with atrial fibrillation who were not treated with anticoagulants was 2.1 (95% confidence interval [CI]: 1.4 to 2.9; P <0.001), whereas the hazard ratio for recurrent severe stroke was 2.4 (95% CI: 1.6 to 3.6; P <0.001). The increased risk was observed even in patients aged > or = 80 years and persisted during the follow-up for more than 5 years. CONCLUSION Atrial fibrillation was an independent risk factor for stroke recurrence over a wide age range.

Assessment of Osteoarthritis Candidate Genes in a Meta-Analysis of Nine Genome-Wide Association Studies

To assess candidate genes for association with osteoarthritis (OA) and identify promising genetic factors and, secondarily, to assess the candidate gene approach in OA.

A meta-analysis of genome-wide association studies identifies novel variants associated with osteoarthritis of the hip

Objectives Osteoarthritis (OA) is the most common form of arthritis with a clear genetic component. To identify novel loci associated with hip OA we performed a meta-analysis of genome-wide association studies (GWAS) on European subjects. Methods We performed a two-stage meta-analysis on more than 78 000 participants. In stage 1, we synthesised data from eight GWAS whereas data from 10 centres were used for ‘in silico’ or ‘de novo’ replication. Besides the main analysis, a stratified by sex analysis was performed to detect possible sex-specific signals. Meta-analysis was performed using inverse-variance fixed effects models. A random effects approach was also used. Results We accumulated 11 277 cases of radiographic and symptomatic hip OA. We prioritised eight single nucleotide polymorphism (SNPs) for follow-up in the discovery stage (4349 OA cases); five from the combined analysis, two male specific and one female specific. One locus, at 20q13, represented by rs6094710 (minor allele frequency (MAF) 4%) near the NCOA3 (nuclear receptor coactivator 3) gene, reached genome-wide significance level with p=7.9×10−9 and OR=1.28 (95% CI 1.18 to 1.39) in the combined analysis of discovery (p=5.6×10−8) and follow-up studies (p=7.3×10−4). We showed that this gene is expressed in articular cartilage and its expression was significantly reduced in OA-affected cartilage. Moreover, two loci remained suggestive associated; rs5009270 at 7q31 (MAF 30%, p=9.9×10−7, OR=1.10) and rs3757837 at 7p13 (MAF 6%, p=2.2×10−6, OR=1.27 in male specific analysis). Conclusions Novel genetic loci for hip OA were found in this meta-analysis of GWAS.