Circulating microRNAs from early childhood and adolescence are associated with pre-diabetes at 18 years of age in women from the PMNS cohort

A high (20%) prevalence of glucose intolerance at 18-years was seen in women from the Pune Maternal Nutrition Study (PMNS) birth cohort. Here, we provide preliminary longitudinal analyses of circulating microRNAs in normal glucose tolerant (NGT@18y, N=10) and glucose intolerant (N=8) women (ADA criteria) at 6-, 12- and 17-years of their age using discovery analysis (OpenArray platform). Machine-learning workflows involving Lasso with bootstrapping/leave-one-out cross-validation (LOOCV) identified microRNAs associated with glucose intolerance at 18-years of age. Several microRNAs, including miR-212-3p, miR-30e-3p and miR-638, stratified glucose-intolerant women from NGT at childhood. Our results suggest that circulating microRNAs in childhood could predict pre-diabetes at 18-years of age. Validation of these findings in males and remaining participants from the PMNS birth cohort will provide a unique opportunity to study novel epigenetic mechanisms in the life-course progression of glucose intolerance and enhance current clinical risk prediction of pre-diabetes and progression to type 2 diabetes.

Life history parameters of the crocodile shark, Pseudocarcharias kamoharai, in the tropical Atlantic Ocean

The crocodile shark (Pseudocarcharias kamoharai) is a small lamniform shark that is occasionally by-caught in pelagic longline fisheries targeting tunas and swordfish. Due to its biological features, this species is highly vulnerable to overexploitation. However, at present, the crocodile shark is not evaluated for its stock status by any of the Regional Fisheries Management Organizations. In this study, the biology of 391 specimens (220 females and 171 males), ranging from 44.2 cm to 101.5 cm fork length (FL), collected from the tropical region of the Atlantic Ocean, was examined. Ages were assigned from growth band counts in vertebral sections, with the modified von Bertalanffy growth model, using a fixed size at birth (L0) at 32 cm FL, producing the best fit: Linf = 105.6 cm FL and k = 0.14 y−1 for females; Linf = 94.6 cm FL and k = 0.18 y−1 for males. Maturity ogives were fitted to both length- and age-based data. The size (L50) and age (A50) at 50% maturity was estimated at 67.2 cm FL (5 years) and 81.6 cm FL (8 years) for males and females, respectively. Mean uterine fecundity was 3.7 pups per litter with a 1:1 embryonic sex ratio. Further work is needed regarding crocodile shark life-history characteristics, especially because there are no age validation studies of the band pair deposition periodicity. However, the parameters now presented can contribute to future evaluations of this species, which is especially important given its potentially vulnerable life history.

Radiocarbon in otoliths of tropical marine fishes: Reference Δ14C chronology for north Caribbean waters

Reef fishes support important fisheries throughout the Caribbean, but a combination of factors in the tropics makes otolith microstructure difficult to interpret for age estimation. Therefore, validation of ageing methods, via application of Δ14C is a major research priority. Utilizing known-age otolith material from north Caribbean fishes, we determined that a distinct regional Δ14C chronology exists, differing from coral-based chronologies compiled for ageing validation from a wide-ranging area of the Atlantic and from an otolith-based chronology from the Gulf of Mexico. Our north Caribbean Δ14C chronology established a decline series with narrow prediction intervals that proved successful in ageing validation of three economically important reef fish species. In examining why our north Caribbean Δ14C chronology differed from some of the coral-based Δ14C data reported from the region, we determined differences among study objectives and research design impact Δ14C temporal relationships. This resulted in establishing the first of three important considerations relevant to applying Δ14C chronologies for ageing validation: 1) evaluation of the applicability of original goal/objectives and study design of potential Δ14C reference studies. Next, we determined differences between our Δ14C chronology and those from Florida and the Gulf of Mexico were explained by differences in regional patterns of oceanic upwelling, resulting in the second consideration for future validation work: 2) evaluation of the applicability of Δ14C reference data to the region/location where fish samples were obtained. Lastly, we emphasize the application of our north Caribbean Δ14C chronology should be limited to ageing validation studies of fishes from this region known to inhabit shallow water coral habitat as juveniles. Thus, we note the final consideration to strengthen findings of future age validation studies: 3) use of Δ14C analysis for age validation should be limited to species whose juvenile habitat is known to reflect the regional Δ14C reference chronology.

Is analysis of otolith microstructure a valid method for investigating early life history of Western Baltic cod?

Daily formation of fish otolith micro-increments is frequently assumed, however applying inferences about timing of life history events and formation of otolith macro-structures requires further validation of the periodicity of micro-increment formation. We analysed micro-increments from Western Baltic cod (WBC, Gadus morhua) otoliths marked with tetracycline-hydrochloride as part of an age validation study to test the assumption of daily formation of micro-increments. We found that the number of counted micro-increments consistently underestimated the age of cod aged 1 and older. Time at liberty was also underestimated, especially for fish at liberty during winter. In contrast, micro-increment counts of otoliths from wild-caught young-of-the-year (YOY) cod could be used to realistically estimate timing of hatch and translucent zone formation. Under ambient conditions, settlement did not correspond to any visible pattern within the otoliths, but could be inferred from the prey switch observed from stomach content analyses. We therefore conclude that micro-increments can be assumed to form on a daily basis until the first winter, and can therefore be used to investigate early life history of YOY WBC. However, the periodicity of micro-increment formation appears to vary seasonally in older individuals, with the number of micro-increments formed during the winter period being particularly low.

Eye lens Δ14C validates otolith-derived age estimates of Gulf of Mexico reef fishes

We tested whether Δ14C values of eye lens protein (crystallin) formed in early life could be utilized to validate marine bony fish age estimates via the bomb radiocarbon chronometer. The slope of the relationship between red snapper (Lutjanus campechanus; n = 8; 0 to 27 years old), otolith and eye lens core Δ14C values was not significantly different than 1, which was also true for seven additional reef fish species (n = 21; 0 to 24 years old). Results demonstrate eye lens core Δ14C can be utilized to validate age estimates of marine fishes, which will be useful in numerous age validation applications.

Growth and Age Validation of the Thornback Ray (Raja clavata Linnaeus, 1758) in the South Adriatic Sea (Central Mediterranean)

Raja clavata is the most widespread and landed skate species in the Mediterranean Basin. Despite its diffusion and economic importance, several aspects of its life history, such as age and growth, are poorly understood. This study evaluated the species’ growth in the South Adriatic Sea (Central Mediterranean Sea) and for the first time attempted an age validation through a tagging experiment. Thin sectioning of vertebral centra proved to be a more accurate preparation method in terms of age estimation precision and reproducibility than whole vertebral centrum staining (cobalt nitrate and ammonium sulfide technique). Marginal analysis showed a clear seasonal pattern, confirming the hypothesis of a single annulus deposition per year. A total of 291 vertebral centra were sampled and used for age estimation purposes. The oldest female was estimated to be 12 years old [total length (TL) = 89 cm], while the oldest male was aged 8 years (TL = 79.9 cm). Females were also found to be characterized by a slightly wider longevity range (ωL = 11.5, ωU = 16.8 years) than males (ωL = 7.8, ωU = 11.2 years). The von Bertalanffy growth curve fit the age and length data more accurately than the Gompertz and logistic models. Eighty-three thornback rays were tagged and released, of which two were recaptured. In both recaptured specimens, oxytetracycline marks were clearly visible. The band deposition after oxytetracycline injection and growth during the freedom period (about 1 year) were consistent with the age estimation method and criteria used and with the obtained growth results. Thus, the analysis of the vertebral centra extracted from the two recaptured specimens confirmed the hypothesis of the deposition of a single annulus per year and in general the age estimation criteria used in this study.

Supercentenarians and Semi-supercentenarians in France

The purpose of this study is twofold. Firstly, it attempts to exhaustively identify cases of French supercentenarians and semi-supercentenarians and to validate their alleged age at death. Secondly, it seeks to uncover careful patterns and trends in probabilities of death and life expectancy at very old ages in France. We use three sets of data with varying degrees of accuracy and coverage: nominative transcripts from the RNIPP (Répertoire national d’identification des personnes physiques), death records from the vital statistics system, and “public” lists of individual supercentenarians. The RNIPP stands out as the most reliable source. Based on all deaths registered in the RNIPP at the alleged ages of 110+ for extinct cohorts born between 1883 and 1901, errors are only few, at least for individuals who were born and died in France. For alleged semi-supercentenarians, age validation on a very large sample shows that errors are extremely rare, suggesting the RNIPP data can be used without any verification until age 108 at the minimum. Moreover, a comparison with “public” lists of individual supercentenarians reveals a single missing occurrence only in the RNIPP transcripts since 1991. While the quality of vital statistics data remains quite deficient at very old ages compared to RNIPP, the analytical results show a significant improvement over time at younger old ages. Our RNIPP-based probabilities of death for females appear to level-off at 0.5 between ages 108 and 111, but data becomes too scarce afterwards to assess the trend. Also, we obtain a quite low life expectancy value of 1.2 years at age 108.

Validation of 113-Year Old Israel Kristal as the World’s Oldest Man

This book chapter provides a detailed description of the discovery, research, and validation of the case of Mr. Israel Kristal of Israel, 113, as the World’s Oldest Man titleholder for Guinness World Records. In this chapter, we show how modern scientific age validation criteria were applied to prove the credibility of the claims made about Mr. Kristal’s age. Due to the hardships Mr. Kristal faced in his early life, validating his age proved to be extremely difficult. While the first attempts to validate Mr. Kristal’s age were made in early 2014, a breakthrough in these investigative efforts did not occur until January 2016. To validate his age, the Gerontology Research Group contacted not only Mr. Kristal’s family, but also international institutions specializing in genealogical research. A special note of appreciation should go to the Jewish Records Indexing in Poland for their contributions to this investigation. As a result of this international cooperation, sufficient early-life, middle-life, and late-life evidence was obtained to meet modern validation standards. Israel Kristal was finally recognized as the oldest living man in the world on Mar. 11, 2016 (retroactive to Jan. 19, 2016). Israel Kristal is the second validated supercentenarian in the history of Israel, after Dr. Maria Pogonowska (1897–2009), who was also born in Poland. In addition, he is the current longevity record-holder of Israel.