Modulation of dendritic spine development and plasticity by BDNF and vesicular trafficking: fundamental roles in neurodevelopmental disorders associated with mental retardation and autism

The process of axonal and dendritic development establishes the synaptic circuitry of the central nervous system (CNS) and is the result of interactions between intrinsic molecular factors and the external environment. One growth factor that has a compelling function in neuronal development is the neurotrophin brain-derived neurotrophic factor (BDNF). BDNF participates in axonal and dendritic differentiation during embryonic stages of neuronal development, as well as in the formation and maturation of dendritic spines during postnatal development. Recent studies have also implicated vesicular trafficking of BDNF via secretory vesicles, and both secretory and endosomal trafficking of vesicles containing synaptic proteins, such as neurotransmitter and neurotrophin receptors, in the regulation of axonal and dendritic differentiation, and in dendritic spine morphogenesis. Several genes that are either mutated or deregulated in neurodevelopmental disorders associated with mental retardation have now been identified, and several mouse models of these disorders have been generated and characterized. Interestingly, abnormalities in dendritic and synaptic structure are consistently observed in human neurodevelopmental disorders associated with mental retardation, and in mouse models of these disorders as well. Abnormalities in dendritic and synaptic differentiation are thought to underlie altered synaptic function and network connectivity, thus contributing to the clinical outcome. Here, we review the roles of BDNF and vesicular trafficking in axonal and dendritic differentiation in the context of dendritic and axonal morphological impairments commonly observed in neurodevelopmental disorders associated with mental retardation

Ilmastonmuutoksen vaikutukset trooppisiin hirmumyrskyihin Pohjois-Atlantilla ja läntisellä Tyynellämerellä

Tässä tutkielmassa tutustutaan trooppisten hirmumyrskyjen syntymekanismeihin sekä sääilmiöihin, jotka vaikuttavat myrskyjen esiintymiseen Pohjois-Atlantilla ja läntisellä osalla Tyyntä valtamerta. Taustalla on ajatus ilmastonmuutoksen vaikutuksista hirmumyrskyjen esiintymiseen, sillä useat tutkijat ovat raportoineet lämpenevän ilmaston suotuisista vaikutuksista trooppisten myrskyjen kehittymisen suhteen. Lämpenevässä ilmastossa odotetaan muutoksia merien pintalämpötiloissa, tuuliolosuhteissa, ilmakehässä sekä sääilmiöissä. Läntisellä Tyynellämerellä ENSO:n voimistuminen ja heikkenevä Walkerin kiertokulku voivat edesauttaa entistä useampien ja voimakkaampien taifuunien esiintymistä alueella. Vastaavasti Pohjois-Atlantilla voimistuva ENSO ja kasvavat vertikaaliset tuulet haittaavat hirmumyrskyjen kehittymistä ja siellä on odotettavissa vähemmän hirmumyrskyaktiivisuutta

Risk of pediatric celiac disease according to HLA haplotype and country

BACKGROUND: The presence of HLA haplotype DR3-DQ2 or DR4-DQ8 is associated with an increased risk of celiac disease. In addition, nearly all children with celiac disease have serum antibodies against tissue transglutaminase (tTG). METHODS: We studied 6403 children with HLA haplotype DR3-DQ2 or DR4-DQ8 prospectively from birth in the United States, Finland, Germany, and Sweden. The primary end point was the development of celiac disease autoimmunity, which was defined as the presence of tTG antibodies on two consecutive tests at least 3 months apart. The secondary end point was the development of celiac disease, which was defined for the purpose of this study as either a diagnosis on biopsy or persistently high levels of tTG antibodies. RESULTS: The median follow-up was 60 months (interquartile range, 46 to 77). Celiac disease autoimmunity developed in 786 children (12%). Of the 350 children who underwent biopsy, 291 had confirmed celiac disease; an additional 21 children who did not undergo biopsy had persistently high levels of tTG antibodies. The risks of celiac disease autoimmunity and celiac disease by the age of 5 years were 11% and 3%, respectively, among children with a single DR3-DQ2 haplotype, and 26% and 11%, respectively, among those with two copies (DR3-DQ2 homozygosity). In the adjusted model, the hazard ratios for celiac disease autoimmunity were 2.09 (95% confidence interval [CI], 1.70 to 2.56) among heterozygotes and 5.70 (95% CI, 4.66 to 6.97) among homozygotes, as compared with children who had the lowest-risk genotypes (DR4-DQ8 heterozygotes or homozygotes). Residence in Sweden was also independently associated with an increased risk of celiac disease autoimmunity (hazard ratio, 1.90; 95% CI, 1.61 to 2.25). CONCLUSIONS: Children with the HLA haplotype DR3-DQ2, especially homozygotes, were found to be at high risk for celiac disease autoimmunity and celiac disease early in childhood. The higher risk in Sweden than in other countries highlights the importance of studying environmental factors associated with celiac disease. (Funded by the National Institute of Diabetes and Digestive and Kidney Diseases and others.)Nejm, free fulltext, erratum: N Engl J Med. 2014 Jul 24;371(4):39

First infant formula type and risk of islet autoimmunity in the environmental determinants of diabetes in the young (TEDDY) study

OBJECTIVE Studies on the introduction of infant formulas and its effect on the risk of islet autoimmunity and type 1 diabetes (T1D) have yielded inconsistent results. We investigated whether the introduction of formula based on hydrolyzed cow'smilk as the first formula is associated with reduced islet autoimmunity risk in a large prospective cohort. RESEARCH DESIGN AND METHODS The Environmental Determinants of Diabetes in the Young (TEDDY) study prospectively monitors 8,676 children at increased genetic risk for T1D. Autoantibodies to insulin, GAD65, and IA2 were measured regularly to define islet autoimmunity. Information on formula feeding was collected by questionnaires at 3 months of age. RESULTS In survival analyses, after adjustment for family history with T1D, HLA genotype, sex, country, delivery mode, breast-feeding 3 months, and seasonality of birth, we observed no significant association with islet autoimmunity in infants who received extensively hydrolyzed compared with nonhydrolyzed cow'smilk-based formula as the first formula during the first 3 months (adjusted hazard ratio 1.38 [95% CI 0.95; 2.01]), and a significantly increased risk for extensively hydrolyzed formula introduced during the first 7 days (adjusted hazard ratio 1.57 [1.04; 2.38]). Using a partially hydrolyzed or other formula as the first formula, or no formula, was not associated with islet autoimmunity risk. CONCLUSIONS These results add to the existing evidence that islet autoimmunity risk is not reduced, and may be increased, by using hydrolyzed compared with nonhydrolyzed cow's milk-based infant formula as the first formula in infants at increased genetic risk for T1D

Factors associated with longitudinal food record compliance in a paediatric cohort study.

Non-compliance with food record submission can induce bias in nutritional epidemiological analysis and make it difficult to draw inference from study findings. We examined the impact of demographic, lifestyle and psychosocial factors on such non-compliance during the first 3 years of participation in a multidisciplinary prospective paediatric study