Does the developmental plasticity hypothesis have application to Irish Travellers? Findings from the all Ireland Traveller Health Study birth cohort 2008-2011.

There is little record of birth weight of Irish Travellers, a minority group in Ireland. Travellers are known to have higher rate of adult chronic disease and to be exposed to life-long disadvantage. The aim of this study was to establish whether the birth weight and infant mortality rate patterns in Ireland's Travellers were consistent with the developmental plasticity hypothesis. A 1-year follow-up birth cohort study was conducted with linkage data from maternity hospital records of Traveller infants born on the island of Ireland over a 12-month period to self-identifying Traveller and general Irish population mothers from the Lifeways Cross-Generation Cohort Study. The main outcome measure was the rate of birth weight <3000 g in a cohort of Traveller children. There were 987 confirmed Traveller births, 500 of whose mothers consented to linkage to their records. A social gradient was observed in the distribution of birth weight in the general population and Traveller infants constituted the highest proportion of all social classes in the birth weight range of 3 kg or less (16.3%). There was a high rate of persistent smoking among Traveller mothers (53%). After adjustment for smoking and alcohol consumption in pregnancy, the birth weight differential persisted (OR 3.5, 95% CI 1.4-8.1). Infant mortality rate at 12.0/1000 births (95% CI 5.5-19.7) was almost four times that of the general population. This analysis confirms Travellers had a greater than expected incidence of low birth weight and high infant mortality with high rates of premature adult chronic diseases from all causes already demonstrated previously.

Getting to the heart of cardiac remodeling; how collagen subtypes may contribute to phenotype.

The objective of this study was to investigate the nature and biomechanical properties of collagen fibers within the human myocardium. Targeting cardiac interstitial abnormalities will likely become a major focus of future preventative strategies with regard to the management of cardiac dysfunction. Current knowledge regarding the component structures of myocardial collagen networks is limited, further delineation of which will require application of more innovative technologies. We applied a novel methodology involving combined confocal laser scanning and atomic force microscopy to investigate myocardial collagen within ex-vivo right atrial tissue from 10 patients undergoing elective coronary bypass surgery. Immuno-fluorescent co-staining revealed discrete collagen I and III fibers. During single fiber deformation, overall median values of stiffness recorded in collagen III were 37±16% lower than in collagen I [p<0.001]. On fiber retraction, collagen I exhibited greater degrees of elastic recoil [p<0.001; relative percentage increase in elastic recoil 7±3%] and less energy dissipation than collagen III [p<0.001; relative percentage increase in work recovered 7±2%]. In atrial biopsies taken from patients in permanent atrial fibrillation (n=5) versus sinus rhythm (n=5), stiffness of both collagen fiber subtypes was augmented (p<0.008). Myocardial fibrillar collagen fibers organize in a discrete manner and possess distinct biomechanical differences; specifically, collagen I fibers exhibit relatively higher stiffness, contrasting with higher susceptibility to plastic deformation and less energy efficiency on deformation with collagen III fibers. Augmented stiffness of both collagen fiber subtypes in tissue samples from patients with atrial fibrillation compared to those in sinus rhythm are consistent with recent published findings of increased collagen cross-linking in this setting.