The transcriptional landscape of age in human peripheral blood

Disease incidences increase with age, but the molecular characteristics of ageing that lead to increased disease susceptibility remain inadequately understood. Here we perform a whole-blood gene expression meta-analysis in 14,983 individuals of European ancestry (including replication) and identify 1,497 genes that are differentially expressed with chronological age. The age-associated genes do not harbor more age-associated CpG-methylation sites than other genes, but are instead enriched for the presence of potentially functional CpG-methylation sites in enhancer and insulator regions that associate with both chronological age and gene expression levels. We further used the gene expression profiles to calculate the 'transcriptomic age' of an individual, and show that differences between transcriptomic age and chronological age are associated with biological features linked to ageing, such as blood pressure, cholesterol levels, fasting glucose, and body mass index. The transcriptomic prediction model adds biological relevance and complements existing epigenetic prediction models, and can be used by others to calculate transcriptomic age in external cohorts.Peer reviewe

Correlation of Measures From the OCULUS Keratograph and Clinical Assessments of Dry Eye Disease in the Dry Eye Assessment and Management Study.

PurposeThe purpose of this study was to compare objective, noninvasive assessments of tear function using the OCULUS Keratograph with the corresponding clinical assessments [tear break-up time (TBUT), Schirmer test, and bulbar erythema] among patients with moderate-to-severe dry eye disease.MethodsParticipants in the Dry Eye Assessment and Management study at centers having an OCULUS Keratograph were assessed using standardized procedures. Associations between the assessments from the Keratograph [noninvasive keratograph break-up time (NIKBUT), tear meniscus height (TMH), and bulbar redness (BR)] and clinical examination (TBUT, Schirmer test, and bulbar erythema) and between these test results and Ocular Surface Disease Index (OSDI) scores were summarized with Spearman correlation coefficients (r s ); 95% confidence intervals (95% CI) accounted for intereye correlation.ResultsAmong 288 patients (576 eyes), the mean (standard deviation) age was 56.6 (13.8) years, 78.1% were female, and the mean baseline OSDI score was 44.3 (14.0). The mean was 2.9 (1.5) seconds for TBUT and 8.2 (5.7) seconds for NIKBUT (their correlation r s = 0.18, 95% CI = 0.09-0.28). The mean was 10.6 (7.6) mm for the Schirmer test and 0.3 (0.2) mm for TMH (r s = 0.15, 95% CI = 0.04-0.25). The median clinical grade redness was mild, and the mean BR score was 1.1 (0.5) (r s = 0.25, 95% CI = 0.15-0.35). Correlation between results of each of the 6 tests and OSDI scores was low (r s from -0.07 to 0.05).ConclusionsIn the Dry Eye Assessment and Management study, NIKBUT, TMH, and BR were weakly correlated with their clinical counterparts. No measurements were correlated with the OSDI score

Missense mutations in COL8A2, the gene encoding the α2 chain of type VIII collagen, cause two forms of corneal endothelial dystrophy

Corneal clarity is maintained by its endothelium, which functions abnormally in the endothelial dystrophies, leading to corneal opacification. This group of conditions includes Fuchs' endothelial dystrophy of the cornea (FECD), one of the commonest indications for corneal transplantation performed in developed countries, posterior polymorphous dystrophy (PPCD) and the congenital hereditary endothelial dystrophies (CHED). A genome-wide search of a three-generation family with early-onset FECD demonstrated significant linkage with D1S2830 (Zmax = 3.72, θ = 0.0). Refinement of the critical region defined a 6-7 cM interval of chromosome 1p34.3-p32 within which lies the COL8A2 gene. This encodes the 703 amino acid α2 chain of type VIII collagen, a short-chain collagen which is a component of endothelial basement membranes and which represented a strong candidate gene. Analysis of its coding sequence defined a missense mutation (gln455lys) within the triple helical domain of the protein in this family. Mutation analysis in patients with FECD and PPCD demonstrated further missense substitutions in familial and sporadic cases of FECD as well as in a single family with PPCD. This is the first description of the molecular basis of any of the corneal endothelial dystrophies or of mutations in type VIII collagen in association with human disease. This suggests that the underlying pathogenesis of FECD and PPCD may be related to disturbance of the role oftype VIII collagen in influencing the terminal differentiation of the neural crest derived corneal endothelial cel