Centenarians exhibit extreme longevity and a remarkable compression of morbidity. They have a unique capacity to maintain homeostatic mechanisms. Since small non-coding RNAs (including microRNAs) are implicated in the regulation of gene expression, we hypothesised that longevity of centenarians may reflect alterations in small non-coding RNA expression. We report the first comparison of microRNAs expression profiles in mononuclear cells from centenarians, octogenarians and young individuals resident near Valencia, Spain. Principal Component Analysis of the expression of 15,644 mature microRNAs and, 2,334 snoRNAs and scaRNAs in centenarians revealed a significant overlap with profiles in young individuals but not with octogenarians and a significant up-regulation of 7 small non-coding RNAs in centenarians compared to young persons and notably 102 small non-coding RNAs when compared with octogenarians. We suggest that the small non-coding RNAs signature in centenarians may provide insights into the underlying molecular mechanisms endowing centenarians with extreme longevity.

Centenarians not only enjoy an extraordinary aging, but also show a compression of morbidity. Using functional transcriptomic analysis of peripheral blood mononuclear cells (PMBC) we identified 1721 mRNAs differentially expressed by centenarians when compared with septuagenarians and young people. Sub-network analysis led us to identify Bcl-xL as an important gene up-regulated in centenarians. It is involved in the control of apoptosis, cellular damage protection and also in modulation of immune response, all associated to healthy aging. Indeed, centenarians display lower plasma cytochrome C levels, higher mitochondrial membrane potential and also less cellular damage accumulation than septuagenarians. Leukocyte chemotaxis and NK cell activity are significantly impaired in septuagenarians compared with young people whereas centenarians maintain them. To further ascertain the functional role of Bcl-xL in cellular aging, we found that lymphocytes from septuagenarians transduced with Bcl-xL display a reduction in senescent-related markers. Finally, to demonstrate the role of Bcl-xL in longevity at the organism level, C. elegans bearing a gain of function mutation in the Bcl-xL ortholog ced-9, showed a significant increase in mean and maximal life span. These results show that mRNA expression in centenarians is unique and reveals that Bcl-xL plays an important role in exceptional aging.

Neonates are at increased risk for developing sepsis, but this population often exhibits ambiguous clinical signs that complicate the diagnosis of infection. No biomarker has yet shown enough diagnostic accuracy to rule out sepsis at the time of clinical suspicion. We show that a gene-expression–based signature is an accurate objective measure of the risk of sepsis in a neonate or preterm infant, and it substantially improves diagnostic accuracy over that of commonly used laboratory-based testing. Implementation might decrease inappropriate antibiotic use. Neonatal sepsis can have devastating consequences, but accurate diagnosis is difficult. As a result, up to 200 neonates with suspected sepsis are treated with empiric antibiotics for every 1 case of microbiologically confirmed sepsis. These unnecessary antibiotics enhance bacterial antibiotic resistance, increase economic costs, and alter gut microbiota composition. We recently reported an 11-gene diagnostic test for sepsis (Sepsis MetaScore) based on host whole-blood gene expression in children and adults, but this test has not been evaluated in neonates. We identified existing gene expression microarray-based cohorts of neonates with sepsis. We then tested the accuracy of the Sepsis MetaScore both alone and in combination with standard diagnostic laboratory tests in diagnosing sepsis. We found 3 cohorts with a total of 213 samples from control neonates and neonates with sepsis. The Sepsis MetaScore had an area under the receiver operating characteristic curve of 0.92–0.93 in all 3 cohorts. We also found that, as a diagnostic test for sepsis, it outperformed standard laboratory measurements alone and, when used in combination with another test(s), resulted in a significant net reclassification index (0.3–0.69) in 5 of 6 comparisons. The mean point estimates for sensitivity and specificity were 95% and 60%, respectively, which, if confirmed prospectively and applied in a high-risk cohort, could reduce inappropriate antibiotic usage substantially. The Sepsis MetaScore had excellent diagnostic accuracy across 3 separate cohorts of neonates from 3 different countries. Further prospective targeted study will be needed before clinical application.

BACKGROUND: Bacterial sepsis is associated with high morbidity and mortality in preterm infants. However, diagnosis of sepsis and identification of the causative agent remains challenging. Our aim was to determine genome-wide expression profiles of very low birth weight (VLBW) infants with and without bacterial sepsis and assess differences. METHODS: This was a prospective observational double-cohort study conducted in VLBW (<1500 g) infants with culture-positive bacterial sepsis and non-septic matched controls. Blood samples were collected as soon as clinical signs of sepsis were identified and before antibiotics were initiated. Total RNA was processed for genome-wide expression analysis using Affymetrix gene arrays. RESULTS: During a 19-month period, 17 septic VLBW infants and 19 matched controls were enrolled. First, a three-dimensional unsupervised principal component analysis based on the entire genome (28 000 transcripts) identified 3 clusters of patients based on gene expression patterns: Gram-positive sepsis, Gram-negative sepsis, and noninfected control infants. Furthermore, these groups were confirmed by using analysis of variance, which identified a transcriptional signature of 554 of genes. These genes had a significantly different expression among the groups. Of the 554 identified genes, 66 belonged to the tumor necrosis factor and 56 to cytokine signaling. The most significantly overexpressed pathways in septic neonates related with innate immune and inflammatory responses and were validated by real-time reverse transcription polymerase chain reaction. CONCLUSIONS: Our preliminary results suggest that genome-wide expression profiles discriminate septic from nonseptic VLBW infants early in the neonatal period. Further studies are needed to confirm these findings.

Sepsis is a life-threatening condition in preterm infants. Neonatal microbiota plays a pivotal role in the immune system maturation. Changes in gut microbiota have been associated to inflammatory disorders; however, a link with sepsis in the neonatal period has not yet been established. We aimed to analyze gut microbiota and mucosal gene expression using non-invasively obtained samples to provide with an integrative perspective of host-microbe interactions in neonatal sepsis. For this purpose, a prospective observational case-control study was conducted in septic preterm dizygotic twins and their non-septic twin controls. Fecal samples were used for both microbiota analysis and host genome-wide expression using exfoliated intestinal cells. Gene expression of exfoliated intestinal cells in septic preterm showed an induction of inflammatory and oxidative stress pathways in the gut and pro-oxidant profile that caused dysbiosis in the gut microbiota with predominance of Enterobacteria and reduction of Bacteroides and Bifidobacterium spp.in fecal samples, leading to a global reduction of beneficial anaerobic bacteria. Sepsis in preterm infants induced low-grade inflammation and oxidative stress in the gut mucosa, and also changes in the gut microbiota. This study highlights the role of inflammation and oxidative stress in neonatal sepsis on gut microbial profiles.