127 research outputs found
Translational Genomics in Legumes Allowed Placing In Silico 5460 Unigenes on the Pea Functional Map and Identified Candidate Genes in Pisum sativum L.
To identify genes involved in phenotypic traits, translational genomics from highly characterized model plants to poorly characterized crop plants provides a valuable source of markers to saturate a zone of interest as well as functionally characterized candidate genes. In this paper, an integrated view of the pea genetic map was developed. A series of gene markers were mapped and their best reciprocal homologs were identified on M. truncatula, L. japonicus, soybean, and poplar pseudomolecules. Based on the syntenic relationships uncovered between pea and M. truncatula, 5460 pea Unigenes were tentatively placed on the consensus map. A new bioinformatics tool, http://www.thelegumeportal.net/pea_mtr_translational_toolkit, was developed that allows, for any gene sequence, to search its putative position on the pea consensus map and hence to search for candidate genes among neighboring Unigenes. As an example, a promising candidate gene for the hypernodulation mutation nod3 in pea was proposed based on the map position of the likely homolog of Pub1, a M. truncatula gene involved in nodulation regulation. A broader view of pea genome evolution was obtained by revealing syntenic relationships between pea and sequenced genomes. Blocks of synteny were identified which gave new insights into the evolution of chromosome structure in Papillionoids and Eudicots. The power of the translational genomics approach was underlined
Excessive Unbalanced Meat Consumption in the First Year of Life Increases Asthma Risk in the PASTURE and LUKAS2 Birth Cohorts.
A higher diversity of food items introduced in the first year of life has been inversely related to subsequent development of asthma. In the current analysis, we applied latent class analysis (LCA) to systematically assess feeding patterns and to relate them to asthma risk at school age. PASTURE (N=1133) and LUKAS2 (N=228) are prospective birth cohort studies designed to evaluate protective and risk factors for atopic diseases, including dietary patterns. Feeding practices were reported by parents in monthly diaries between the 4th and 12th month of life. For 17 common food items parents indicated frequency of feeding during the last 4 weeks in 4 categories. The resulting 153 ordinal variables were entered in a LCA. The intestinal microbiome was assessed at the age of 12 months by 16S rRNA sequencing. Data on feeding practice with at least one reported time point was available in 1042 of the 1133 recruited children. Best LCA model fit was achieved by the 4-class solution. One class showed an elevated risk of asthma at age 6 as compared to the other classes (adjusted odds ratio (aOR): 8.47, 95% CI 2.52-28.56, p = 0.001) and was characterized by daily meat consumption and rare consumption of milk and yoghurt. A refined LCA restricted to meat, milk, and yoghurt confirmed the asthma risk effect of a particular class in PASTURE and independently in LUKAS2, which we thus termed unbalanced meat consumption (UMC). The effect of UMC was particularly strong for non-atopic asthma and asthma irrespectively of early bronchitis (aOR: 17.0, 95% CI 5.2-56.1, p < 0.001). UMC fostered growth of iron scavenging bacteria such as Acinetobacter (aOR: 1.28, 95% CI 1.00-1.63, p = 0.048), which was also related to asthma (aOR: 1.55, 95% CI 1.18-2.03, p = 0.001). When reconstructing bacterial metabolic pathways from 16S rRNA sequencing data, biosynthesis of siderophore group nonribosomal peptides emerged as top hit (aOR: 1.58, 95% CI 1.13-2.19, p = 0.007). By a data-driven approach we found a pattern of overly meat consumption at the expense of other protein sources to confer risk of asthma. Microbiome analysis of fecal samples pointed towards overgrowth of iron-dependent bacteria and bacterial iron metabolism as a potential explanation
Continuous Rather Than Solely Early Farm Exposure Protects From Hay Fever Development
BACKGROUND: An important window of opportunity for early-life exposures has been proposed for the development of atopic eczema and asthma.OBJECTIVE: However, it is unknown whether hay fever with a peak incidence around late school age to adolescence is similarly determined very early in life.METHODS: In the Protection against Allergy-Study in Rural Environments (PASTURE) birth cohort potentially relevant exposures such as farm milk consumption and exposure to animal sheds were assessed at multiple time points from infancy to age 10.5 years and classified by repeated measure latent class analyses (n [ 769). Fecal samples at ages 2 and 12 months were sequenced by 16S rRNA. Hay fever was defined by parent -reported symptoms and/or physician's diagnosis of hay fever in the last 12 months using questionnaires at 10.5 years.RESULTS: Farm children had half the risk of hay fever at 10.5 years (adjusted odds ratio [aOR] 0.50; 95% CI 0.31-0.79) than that of nonfarm children. Whereas early life events such as gut microbiome richness at 12 months (aOR 0.66; 95% CI 0.46-0.96) and exposure to animal sheds in the first 3 years of life (aOR 0.26; 95% CI 0.06-1.15) were determinants of hay fever, the continuous consumption of farm milk from infancy up to school age was necessary to exert the protective effect (aOR 0.35; 95% CI 0.17-0.72).CONCLUSIONS: While early life events determine the risk of subsequent hay fever, continuous exposure is necessary to achieve protection. These findings argue against the notion that only early life exposures set long-lasting trajectories. (c) 2022 The Authors. Published by Elsevier IncPeer reviewe
Maturation of the gut microbiome during the first year of life contributes to the protective farm effect on childhood asthma
Peer reviewedPostprin
An integrated molecular risk score early in life for subsequent childhood asthma risk.
BACKGROUND
Numerous children present with early wheeze symptoms, yet solely a subgroup develops childhood asthma. Early identification of children at risk is key for clinical monitoring, timely patient-tailored treatment, and preventing chronic, severe sequelae. For early prediction of childhood asthma, we aimed to define an integrated risk score combining established risk factors with genome-wide molecular markers at birth, complemented by subsequent clinical symptoms/diagnoses (wheezing, atopic dermatitis, food allergy).
METHODS
Three longitudinal birth cohorts (PAULINA/PAULCHEN, nâ=â190â+â93â=â283, PASTURE, nâ=â1133) were used to predict childhood asthma (age 5-11) including epidemiological characteristics and molecular markers: genotype, DNA methylation and mRNA expression (RNASeq/NanoString). Apparent (ap) and optimism-corrected (oc) performance (AUC/R2) was assessed leveraging evidence from independent studies (NaĂŻve-Bayes approach) combined with high-dimensional logistic regression models (LASSO).
RESULTS
Asthma prediction with epidemiological characteristics at birth (maternal asthma, sex, farm environment) yielded an ocAUCâ=â0.65. Inclusion of molecular markers as predictors resulted in an improvement in apparent prediction performance, however, for optimism-corrected performance only a moderate increase was observed (upto ocAUCâ=â0.68). The greatest discriminate power was reached by adding the first symptoms/diagnosis (up to ocAUCâ=â0.76; increase of 0.08, pâ=â.002). Longitudinal analysis of selected mRNA expression in PASTURE (cord blood, 1, 4.5, 6âyears) showed that expression at age six had the strongest association with asthma and correlation of genes getting larger over time (râ=â.59, pâ<â.001, 4.5-6âyears).
CONCLUSION
Applying epidemiological predictors alone showed moderate predictive abilities. Molecular markers from birth modestly improved prediction. Allergic symptoms/diagnoses enhanced the power of prediction, which is important for clinical practice and for the design of future studies with molecular markers
La toux en dehors d'une infection chez l'enfant : trajectoires au cours des dix premiÚres années de vie, association avec les maladies allergiques et rÎle de l'environnement périnatal
Cough is a frequent and non-specific respiratory symptom in children. In the majority of otherwise healthy children, cough is a symptom related to a self-limiting viral upper respiratory tract infection. However, some children have cough hypersensitivy that manifests as frequent or recurrent coughs, without a respiratory infection, and triggered by normally innocuous stimuli. Although atopy is one of the etiological mechanisms of this hypersensitivity, few studies has explored the relationship between cough trajectories in children and allergic diseases, as well as their association with early environment.In order to identify trajectories of cough in childhood, to analyse their relationship with allergic diseases and with early environment, the thesis work consisted of two complementary parts: an epidemiological observational part in children and an experimental part in rabbit. The epidemiological part was based on analysis of data from the prospective European birth cohort PASTURE (Protection against Allergy: STUdy in Rural Environment). Among the 961 children included in the epidemiological study, a latent class analysis allowed to identify five trajectories of cough without a cold: never of infrequent (59.9%), acute transient (24.1%), moderate transient (6.8%), late persistent (4.8%) and early persistent (4.4%). Compared with the never/infrequent trajectory, the other trajectories were significantly associated with wheezing, asthma and allergic rhinitis. Early persistent trajectory had the strongest association with asthma and was inversely associated with farm environment. Food allergy was associated with both persistent trajectories. Atopic sensitisation was only associated with the late persistent trajectory. Consumption of boiled farm milk during the first year of life was the only farm-specific exposure significantly associated with a decreased risk of early persistent cough and acute transient cough. Repeated or prolonged respiratory tract infections during the first year of life was associated with a higher risk of early persistent cough. The experimental part allowed to evaluate the impact of perinatal exposure to farm dust on cough sensitivity and airway responsiveness in an allergic airway inflammation rabbit model. A specific environment has been applied to pregnant rabbits and their offspring until six weeks after birth (pathogen-free zone for the control group, calf barn for the farm group). Rabbit pups were then housed in a conventional zone and sensitised to ovalbumin by intraperitoneal route. Cough sensitivity was assessed by mechanical stimulation of cough and airway responsiveness by a methacholine challenge. We did not find any effect of early exposure to the calf barn on cough sensitivity or bronchial reactivity.Our results suggest 1/ a close link between persistent cough and atopic diseases and 2/ the existence of potential common preventive factors. Children having persistent or recurrent cough should be referred to an allergist for a complete allergy assessment. Prevention studies for atopic diseases should also explored symptoms of cough without a cold in order to evaluate the relevance of developing common prevention strategies.La toux est un symptĂŽme respiratoire frĂ©quent et non spĂ©cifique chez lâenfant, habituellement prĂ©sent uniquement durant une infection aigue des voies respiratoires. Cependant, certains enfants prĂ©sentent une toux par excĂšs de sensibilitĂ© se manifestant par des Ă©pisodes de toux frĂ©quents ou rĂ©currents, en dehors dâune infection, et des facteurs dĂ©clenchants habituellement non tussigĂšnes. Bien quâun des mĂ©canismes Ă©tiologiques de cette hypersensibilitĂ© soit lâatopie, trĂšs peu dâĂ©tudes se sont intĂ©ressĂ©es Ă la relation entre trajectoires de toux dans lâenfance et maladies allergiques ainsi quâĂ leur association avec lâenvironnement prĂ©coce.Afin dâidentifier les trajectoires de toux dans lâenfance, dâanalyser leur relation avec les maladies allergiques et avec lâenvironnement prĂ©coce, le travail de cette thĂšse a portĂ© sur deux volets complĂ©mentaires : un volet Ă©pidĂ©miologique observationnel chez lâenfant et un volet expĂ©rimental chez le lapin. Le volet Ă©pidĂ©miologique reposait sur lâanalyse des donnĂ©es de la cohorte prospective europĂ©enne PASTURE (Protection against Allergy: STUdy in Rural Environment). Parmi les 961 enfants inclus dans lâĂ©tude Ă©pidĂ©miologique, une analyse en classes latentes a permis dâidentifier cinq trajectoires de toux en dehors dâune infection : peu ou pas de symptĂŽmes (59,9 %), transitoire aigue (24,1 %), transitoire modĂ©rĂ©e (6,8 %), persistante Ă dĂ©but tardif (4,8 %), et persistante Ă dĂ©but prĂ©coce (4,4 %). En comparaison avec la trajectoire peu ou pas de symptĂŽmes, les autres trajectoires Ă©taient significativement associĂ©es avec les sibilants, lâasthme et la rhinite allergique. La trajectoire persistante Ă dĂ©but prĂ©coce avait la plus forte association pour lâasthme et Ă©tait inversement associĂ©e Ă lâenvironnement fermier. Lâallergie alimentaire Ă©tait associĂ©e aux deux trajectoires persistantes. La sensibilisation atopique Ă©tait associĂ©e uniquement Ă la toux persistante Ă dĂ©but tardif. La consommation de lait de ferme bouilli durant la premiĂšre annĂ©e de vie Ă©tait la seule exposition spĂ©cifique Ă lâenvironnement fermier significativement associĂ©e Ă une diminution du risque de toux persistante Ă dĂ©but prĂ©coce et de toux transitoire aigue. Des infections respiratoires rĂ©pĂ©tĂ©es ou prolongĂ©es dans la premiĂšre annĂ©e de vie Ă©taient significativement associĂ©es Ă un risque plus Ă©levĂ© de toux persistante Ă dĂ©but prĂ©coce. Le volet expĂ©rimental a permis dâĂ©valuer lâimpact de lâexposition pĂ©rinatale Ă la poussiĂšre de ferme sur la sensibilitĂ© tussigĂšne et la rĂ©activitĂ© bronchique chez un modĂšle de lapin dâinflammation bronchique dâorigine allergique. Un environnement spĂ©cifique a Ă©tĂ© appliquĂ© aux lapines gestantes et Ă leurs lapereaux jusquâĂ la sixiĂšme semaine de vie (zone exempte dâagent pathogĂšne pour le groupe contrĂŽle ; Ă©table de veaux pour le groupe ferme). Les lapereaux Ă©taient ensuite hĂ©bergĂ©s dans une zone conventionnelle de lâanimalerie et sensibilisĂ©s Ă lâovalbumine par voie intrapĂ©ritonĂ©ale. La sensibilitĂ© Ă la toux a Ă©tĂ© Ă©valuĂ©e par la stimulation mĂ©canique de la toux et la rĂ©activitĂ© bronchique par un test Ă la mĂ©thacholine. Nous nâavons pas retrouvĂ© dâeffet de lâexposition prĂ©coce Ă une Ă©table de veaux sur la sensibilitĂ© tussigĂšne ni la rĂ©activitĂ© bronchique.Nos rĂ©sultats suggĂšrent un lien Ă©troit entre toux persistante et pathologies atopiques ainsi que lâexistence de potentiels facteurs de prĂ©vention communs. Les enfants prĂ©sentant une toux persistante ou rĂ©currente devraient ĂȘtre orientĂ©s vers un mĂ©decin allergologue pour quâune Ă©valuation allergologique complĂšte soit rĂ©alisĂ©e. Les Ă©tudes de prĂ©vention des pathologies atopiques devraient Ă©galement sâintĂ©resser aux symptĂŽmes de toux en dehors dâune infection afin dâĂ©valuer la pertinence de dĂ©velopper des stratĂ©gies de prĂ©vention communes
La toux en dehors d'une infection chez l'enfant : trajectoires au cours des dix premiÚres années de vie, association avec les maladies allergiques et rÎle de l'environnement périnatal
Cough is a frequent and non-specific respiratory symptom in children. In the majority of otherwise healthy children, cough is a symptom related to a self-limiting viral upper respiratory tract infection. However, some children have cough hypersensitivy that manifests as frequent or recurrent coughs, without a respiratory infection, and triggered by normally innocuous stimuli. Although atopy is one of the etiological mechanisms of this hypersensitivity, few studies has explored the relationship between cough trajectories in children and allergic diseases, as well as their association with early environment.In order to identify trajectories of cough in childhood, to analyse their relationship with allergic diseases and with early environment, the thesis work consisted of two complementary parts: an epidemiological observational part in children and an experimental part in rabbit. The epidemiological part was based on analysis of data from the prospective European birth cohort PASTURE (Protection against Allergy: STUdy in Rural Environment). Among the 961 children included in the epidemiological study, a latent class analysis allowed to identify five trajectories of cough without a cold: never of infrequent (59.9%), acute transient (24.1%), moderate transient (6.8%), late persistent (4.8%) and early persistent (4.4%). Compared with the never/infrequent trajectory, the other trajectories were significantly associated with wheezing, asthma and allergic rhinitis. Early persistent trajectory had the strongest association with asthma and was inversely associated with farm environment. Food allergy was associated with both persistent trajectories. Atopic sensitisation was only associated with the late persistent trajectory. Consumption of boiled farm milk during the first year of life was the only farm-specific exposure significantly associated with a decreased risk of early persistent cough and acute transient cough. Repeated or prolonged respiratory tract infections during the first year of life was associated with a higher risk of early persistent cough. The experimental part allowed to evaluate the impact of perinatal exposure to farm dust on cough sensitivity and airway responsiveness in an allergic airway inflammation rabbit model. A specific environment has been applied to pregnant rabbits and their offspring until six weeks after birth (pathogen-free zone for the control group, calf barn for the farm group). Rabbit pups were then housed in a conventional zone and sensitised to ovalbumin by intraperitoneal route. Cough sensitivity was assessed by mechanical stimulation of cough and airway responsiveness by a methacholine challenge. We did not find any effect of early exposure to the calf barn on cough sensitivity or bronchial reactivity.Our results suggest 1/ a close link between persistent cough and atopic diseases and 2/ the existence of potential common preventive factors. Children having persistent or recurrent cough should be referred to an allergist for a complete allergy assessment. Prevention studies for atopic diseases should also explored symptoms of cough without a cold in order to evaluate the relevance of developing common prevention strategies.La toux est un symptĂŽme respiratoire frĂ©quent et non spĂ©cifique chez lâenfant, habituellement prĂ©sent uniquement durant une infection aigue des voies respiratoires. Cependant, certains enfants prĂ©sentent une toux par excĂšs de sensibilitĂ© se manifestant par des Ă©pisodes de toux frĂ©quents ou rĂ©currents, en dehors dâune infection, et des facteurs dĂ©clenchants habituellement non tussigĂšnes. Bien quâun des mĂ©canismes Ă©tiologiques de cette hypersensibilitĂ© soit lâatopie, trĂšs peu dâĂ©tudes se sont intĂ©ressĂ©es Ă la relation entre trajectoires de toux dans lâenfance et maladies allergiques ainsi quâĂ leur association avec lâenvironnement prĂ©coce.Afin dâidentifier les trajectoires de toux dans lâenfance, dâanalyser leur relation avec les maladies allergiques et avec lâenvironnement prĂ©coce, le travail de cette thĂšse a portĂ© sur deux volets complĂ©mentaires : un volet Ă©pidĂ©miologique observationnel chez lâenfant et un volet expĂ©rimental chez le lapin. Le volet Ă©pidĂ©miologique reposait sur lâanalyse des donnĂ©es de la cohorte prospective europĂ©enne PASTURE (Protection against Allergy: STUdy in Rural Environment). Parmi les 961 enfants inclus dans lâĂ©tude Ă©pidĂ©miologique, une analyse en classes latentes a permis dâidentifier cinq trajectoires de toux en dehors dâune infection : peu ou pas de symptĂŽmes (59,9 %), transitoire aigue (24,1 %), transitoire modĂ©rĂ©e (6,8 %), persistante Ă dĂ©but tardif (4,8 %), et persistante Ă dĂ©but prĂ©coce (4,4 %). En comparaison avec la trajectoire peu ou pas de symptĂŽmes, les autres trajectoires Ă©taient significativement associĂ©es avec les sibilants, lâasthme et la rhinite allergique. La trajectoire persistante Ă dĂ©but prĂ©coce avait la plus forte association pour lâasthme et Ă©tait inversement associĂ©e Ă lâenvironnement fermier. Lâallergie alimentaire Ă©tait associĂ©e aux deux trajectoires persistantes. La sensibilisation atopique Ă©tait associĂ©e uniquement Ă la toux persistante Ă dĂ©but tardif. La consommation de lait de ferme bouilli durant la premiĂšre annĂ©e de vie Ă©tait la seule exposition spĂ©cifique Ă lâenvironnement fermier significativement associĂ©e Ă une diminution du risque de toux persistante Ă dĂ©but prĂ©coce et de toux transitoire aigue. Des infections respiratoires rĂ©pĂ©tĂ©es ou prolongĂ©es dans la premiĂšre annĂ©e de vie Ă©taient significativement associĂ©es Ă un risque plus Ă©levĂ© de toux persistante Ă dĂ©but prĂ©coce. Le volet expĂ©rimental a permis dâĂ©valuer lâimpact de lâexposition pĂ©rinatale Ă la poussiĂšre de ferme sur la sensibilitĂ© tussigĂšne et la rĂ©activitĂ© bronchique chez un modĂšle de lapin dâinflammation bronchique dâorigine allergique. Un environnement spĂ©cifique a Ă©tĂ© appliquĂ© aux lapines gestantes et Ă leurs lapereaux jusquâĂ la sixiĂšme semaine de vie (zone exempte dâagent pathogĂšne pour le groupe contrĂŽle ; Ă©table de veaux pour le groupe ferme). Les lapereaux Ă©taient ensuite hĂ©bergĂ©s dans une zone conventionnelle de lâanimalerie et sensibilisĂ©s Ă lâovalbumine par voie intrapĂ©ritonĂ©ale. La sensibilitĂ© Ă la toux a Ă©tĂ© Ă©valuĂ©e par la stimulation mĂ©canique de la toux et la rĂ©activitĂ© bronchique par un test Ă la mĂ©thacholine. Nous nâavons pas retrouvĂ© dâeffet de lâexposition prĂ©coce Ă une Ă©table de veaux sur la sensibilitĂ© tussigĂšne ni la rĂ©activitĂ© bronchique.Nos rĂ©sultats suggĂšrent un lien Ă©troit entre toux persistante et pathologies atopiques ainsi que lâexistence de potentiels facteurs de prĂ©vention communs. Les enfants prĂ©sentant une toux persistante ou rĂ©currente devraient ĂȘtre orientĂ©s vers un mĂ©decin allergologue pour quâune Ă©valuation allergologique complĂšte soit rĂ©alisĂ©e. Les Ă©tudes de prĂ©vention des pathologies atopiques devraient Ă©galement sâintĂ©resser aux symptĂŽmes de toux en dehors dâune infection afin dâĂ©valuer la pertinence de dĂ©velopper des stratĂ©gies de prĂ©vention communes
Cough without a cold in children : trajectories in the first ten years of life, association with allergic diseases and role of perinatal environment
La toux est un symptĂŽme respiratoire frĂ©quent et non spĂ©cifique chez lâenfant, habituellement prĂ©sent uniquement durant une infection aigue des voies respiratoires. Cependant, certains enfants prĂ©sentent une toux par excĂšs de sensibilitĂ© se manifestant par des Ă©pisodes de toux frĂ©quents ou rĂ©currents, en dehors dâune infection, et des facteurs dĂ©clenchants habituellement non tussigĂšnes. Bien quâun des mĂ©canismes Ă©tiologiques de cette hypersensibilitĂ© soit lâatopie, trĂšs peu dâĂ©tudes se sont intĂ©ressĂ©es Ă la relation entre trajectoires de toux dans lâenfance et maladies allergiques ainsi quâĂ leur association avec lâenvironnement prĂ©coce.Afin dâidentifier les trajectoires de toux dans lâenfance, dâanalyser leur relation avec les maladies allergiques et avec lâenvironnement prĂ©coce, le travail de cette thĂšse a portĂ© sur deux volets complĂ©mentaires : un volet Ă©pidĂ©miologique observationnel chez lâenfant et un volet expĂ©rimental chez le lapin. Le volet Ă©pidĂ©miologique reposait sur lâanalyse des donnĂ©es de la cohorte prospective europĂ©enne PASTURE (Protection against Allergy: STUdy in Rural Environment). Parmi les 961 enfants inclus dans lâĂ©tude Ă©pidĂ©miologique, une analyse en classes latentes a permis dâidentifier cinq trajectoires de toux en dehors dâune infection : peu ou pas de symptĂŽmes (59,9 %), transitoire aigue (24,1 %), transitoire modĂ©rĂ©e (6,8 %), persistante Ă dĂ©but tardif (4,8 %), et persistante Ă dĂ©but prĂ©coce (4,4 %). En comparaison avec la trajectoire peu ou pas de symptĂŽmes, les autres trajectoires Ă©taient significativement associĂ©es avec les sibilants, lâasthme et la rhinite allergique. La trajectoire persistante Ă dĂ©but prĂ©coce avait la plus forte association pour lâasthme et Ă©tait inversement associĂ©e Ă lâenvironnement fermier. Lâallergie alimentaire Ă©tait associĂ©e aux deux trajectoires persistantes. La sensibilisation atopique Ă©tait associĂ©e uniquement Ă la toux persistante Ă dĂ©but tardif. La consommation de lait de ferme bouilli durant la premiĂšre annĂ©e de vie Ă©tait la seule exposition spĂ©cifique Ă lâenvironnement fermier significativement associĂ©e Ă une diminution du risque de toux persistante Ă dĂ©but prĂ©coce et de toux transitoire aigue. Des infections respiratoires rĂ©pĂ©tĂ©es ou prolongĂ©es dans la premiĂšre annĂ©e de vie Ă©taient significativement associĂ©es Ă un risque plus Ă©levĂ© de toux persistante Ă dĂ©but prĂ©coce. Le volet expĂ©rimental a permis dâĂ©valuer lâimpact de lâexposition pĂ©rinatale Ă la poussiĂšre de ferme sur la sensibilitĂ© tussigĂšne et la rĂ©activitĂ© bronchique chez un modĂšle de lapin dâinflammation bronchique dâorigine allergique. Un environnement spĂ©cifique a Ă©tĂ© appliquĂ© aux lapines gestantes et Ă leurs lapereaux jusquâĂ la sixiĂšme semaine de vie (zone exempte dâagent pathogĂšne pour le groupe contrĂŽle ; Ă©table de veaux pour le groupe ferme). Les lapereaux Ă©taient ensuite hĂ©bergĂ©s dans une zone conventionnelle de lâanimalerie et sensibilisĂ©s Ă lâovalbumine par voie intrapĂ©ritonĂ©ale. La sensibilitĂ© Ă la toux a Ă©tĂ© Ă©valuĂ©e par la stimulation mĂ©canique de la toux et la rĂ©activitĂ© bronchique par un test Ă la mĂ©thacholine. Nous nâavons pas retrouvĂ© dâeffet de lâexposition prĂ©coce Ă une Ă©table de veaux sur la sensibilitĂ© tussigĂšne ni la rĂ©activitĂ© bronchique.Nos rĂ©sultats suggĂšrent un lien Ă©troit entre toux persistante et pathologies atopiques ainsi que lâexistence de potentiels facteurs de prĂ©vention communs. Les enfants prĂ©sentant une toux persistante ou rĂ©currente devraient ĂȘtre orientĂ©s vers un mĂ©decin allergologue pour quâune Ă©valuation allergologique complĂšte soit rĂ©alisĂ©e. Les Ă©tudes de prĂ©vention des pathologies atopiques devraient Ă©galement sâintĂ©resser aux symptĂŽmes de toux en dehors dâune infection afin dâĂ©valuer la pertinence de dĂ©velopper des stratĂ©gies de prĂ©vention communes.Cough is a frequent and non-specific respiratory symptom in children. In the majority of otherwise healthy children, cough is a symptom related to a self-limiting viral upper respiratory tract infection. However, some children have cough hypersensitivy that manifests as frequent or recurrent coughs, without a respiratory infection, and triggered by normally innocuous stimuli. Although atopy is one of the etiological mechanisms of this hypersensitivity, few studies has explored the relationship between cough trajectories in children and allergic diseases, as well as their association with early environment.In order to identify trajectories of cough in childhood, to analyse their relationship with allergic diseases and with early environment, the thesis work consisted of two complementary parts: an epidemiological observational part in children and an experimental part in rabbit. The epidemiological part was based on analysis of data from the prospective European birth cohort PASTURE (Protection against Allergy: STUdy in Rural Environment). Among the 961 children included in the epidemiological study, a latent class analysis allowed to identify five trajectories of cough without a cold: never of infrequent (59.9%), acute transient (24.1%), moderate transient (6.8%), late persistent (4.8%) and early persistent (4.4%). Compared with the never/infrequent trajectory, the other trajectories were significantly associated with wheezing, asthma and allergic rhinitis. Early persistent trajectory had the strongest association with asthma and was inversely associated with farm environment. Food allergy was associated with both persistent trajectories. Atopic sensitisation was only associated with the late persistent trajectory. Consumption of boiled farm milk during the first year of life was the only farm-specific exposure significantly associated with a decreased risk of early persistent cough and acute transient cough. Repeated or prolonged respiratory tract infections during the first year of life was associated with a higher risk of early persistent cough. The experimental part allowed to evaluate the impact of perinatal exposure to farm dust on cough sensitivity and airway responsiveness in an allergic airway inflammation rabbit model. A specific environment has been applied to pregnant rabbits and their offspring until six weeks after birth (pathogen-free zone for the control group, calf barn for the farm group). Rabbit pups were then housed in a conventional zone and sensitised to ovalbumin by intraperitoneal route. Cough sensitivity was assessed by mechanical stimulation of cough and airway responsiveness by a methacholine challenge. We did not find any effect of early exposure to the calf barn on cough sensitivity or bronchial reactivity.Our results suggest 1/ a close link between persistent cough and atopic diseases and 2/ the existence of potential common preventive factors. Children having persistent or recurrent cough should be referred to an allergist for a complete allergy assessment. Prevention studies for atopic diseases should also explored symptoms of cough without a cold in order to evaluate the relevance of developing common prevention strategies
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