Genetic, parental and lifestyle factors influence telomere length

The average length of telomere repeats (TL) declines with age and is considered to be a marker of biological ageing. Here, we measured TL in six blood cell types from 1046 individuals using the clinically validated Flow-FISH method. We identified remarkable cell-type-specific variations in TL. Host genetics, environmental, parental and intrinsic factors such as sex, parental age, and smoking are associated to variations in TL. By analysing the genome-wide methylation patterns, we identified that the association of maternal, but not paternal, age to TL is mediated by epigenetics. Single-cell RNA-sequencing data for 62 participants revealed differential gene expression in T-cells. Genes negatively associated with TL were enriched for pathways related to translation and nonsense-mediated decay. Altogether, this study addresses cell-type-specific differences in telomere biology and its relation to cell-type-specific gene expression and highlights how perinatal factors play a role in determining TL, on top of genetics and lifestyle.We thank J. Dekens for management, A. Maatman and M. Platteel for technical support and K. Mc Intyre for English editing. This project was funded by the BBMRI grant for measuring telomere length and by a Rosalind Franklin Fellowship to A.Z. The researchers participated in this project are supported by Netherlands Heart Foundation (IN-CONTROL CVON grants 2012-03 and 2018-27); the Netherlands Organization for Scientific Research (NWO) Gravitation Netherlands Organ-on-Chip Initiative to J.F. and C.W.; NWO Gravitation Exposome-NL (024.004.017) to J.F., A.K. and A.Z.; NWO-VIDI (864.13.013) and NWO-VICI (VI.C.202.022) to J.F.; NWO-VIDI (016.178.056) to A.Z.; NWO-VIDI (917.14.374) to L.F.; NWO-VENI (194.006) to D.V.Z.; NWO-VENI (192.029) to M.W.; NWO Spinoza Prize SPI 92–266 to C.W.; the European Research Council (ERC) (FP7/2007–2013/ERC Advanced Grant 2012-322698) to C.W.; ERC Starting grant 637640 to L.F.; ERC Starting Grant 715772 to A.Z.; ERC Consolidator Grant (grant agreement No. 101001678) to J.F.; and RuG Investment Agenda Grant Personalized Health to C.W. MM work is supported by RYC- 2017-22249 and PID2019-107937GA-I00 grants. T.S. holds scholarships from the Junior Scientific Masterclass, University of Groningen[grant no. 17–34]. AR is funded by a Formación Personal Investigador (FPI) grant [grant no. PRE2019-090193]. The Lifelines Biobank initiative has been made possible by a subsidy from the Dutch Ministry of Health, Welfare and Sport; the Dutch Ministry of Economic Affairs; the University Medical Centre Groningen (UMCG, the Netherlands); the University of Groningen and the Northern Provinces of the Netherlands. The authors wish to acknowledge the services of the Lifelines Cohort Study, the contributing research centres delivering data to Lifelines and all the study participants. Finally, we would like to acknowledge the Genomics Coordination Centre (GCC) at the University Medical College Groningen for the HPC support and the MOLGENIS team for the cloud storage of the data associated with this work.Peer Reviewed"Article signat per 16 autors/es: Sergio Andreu-Sánchez, Geraldine Aubert, Aida Ripoll-Cladellas, Sandra Henkelman, Daria V. Zhernakova, Trishla Sinha, Alexander Kurilshikov, Maria Carmen Cenit, Marc Jan Bonder, Lude Franke, Cisca Wijmenga, Jingyuan Fu, Monique G. P. van der Wijst, Marta Melé, Peter Lansdorp & Alexandra Zhernakova"Postprint (published version

Fat metabolism is associated with telomere length in six population-based studies

Telomeres are repetitive DNA sequences located at the end of chromosomes, which are associated to biological aging, cardiovascular disease, cancer and mortality. Lipid and fatty acid metabolism have been associated with telomere shortening. We have conducted an in-depth study investigating the association of metabolic biomarkers with telomere length (LTL). We performed an association analysis of 226 metabolic biomarkers with LTL using data from 11 775 individuals from six independent population-based cohorts (BBMRI-NL consortium). Metabolic biomarkers include lipoprotein lipids and subclasses, fatty acids, amino acids, glycolysis measures and ketone bodies. LTL was measured by quantitative polymerase chain reaction or FlowFISH. Linear regression analysis was performed adjusting for age, sex, lipid-lowering medication and cohort-specific covariates (model 1) and additionally for body mass index (BMI) and smoking (model 2), followed by inverse variance-weighted meta-analyses (significance threshold Pmeta = 6.5 × 10-4). We identified four metabolic biomarkers positively associated with LTL, including two cholesterol to lipid ratios in small VLDL (S-VLDL-C % and S-VLDL-CE %) and two omega-6 fatty acid ratios (FAw6/FA and LA/FA). After additionally adjusting for BMI and smoking, these metabolic biomarkers remained associated with LTL with similar effect estimates. In addition, cholesterol esters in very small VLDL (XS-VLDL-CE) became significantly associated with LTL (P = 3.6 × 10-4). We replicated the association of FAw6/FA with LTL in an independent dataset of 7845 individuals (P = 1.9 × 10-4). To conclude, we identified multiple metabolic biomarkers involved in lipid and fatty acid metabolism that may be involved in LTL biology. Longitudinal studies are needed to exclude reversed causation

Genetic, parental and lifestyle factors influence telomere length

The average length of telomere repeats (TL) declines with age and is considered to be a marker of biological ageing. Here, we measured TL in six blood cell types from 1046 individuals using the clinically validated Flow-FISH method. We identified remarkable cell-type-specific variations in TL. Host genetics, environmental, parental and intrinsic factors such as sex, parental age, and smoking are associated to variations in TL. By analysing the genome-wide methylation patterns, we identified that the association of maternal, but not paternal, age to TL is mediated by epigenetics. Single-cell RNA-sequencing data for 62 participants revealed differential gene expression in T-cells. Genes negatively associated with TL were enriched for pathways related to translation and nonsense-mediated decay. Altogether, this study addresses cell-type-specific differences in telomere biology and its relation to cell-type-specific gene expression and highlights how perinatal factors play a role in determining TL, on top of genetics and lifestyle.This project was funded by the BBMRI grant for measuring telomere length and by a Rosalind Franklin Fellowship to A.Z. The researchers participated in this project are supported by Netherlands Heart Foundation (IN-CONTROL CVON grants 2012-03 and 2018-27); the Netherlands Organization for Scientific Research (NWO) Gravitation Netherlands Organ-on-Chip Initiative to J.F. and C.W.; NWO Gravitation Exposome-NL (024.004.017) to J.F., A.K. and A.Z.; NWO-VIDI (864.13.013) and NWO-VICI (VI.C.202.022) to J.F.; NWO-VIDI (016.178.056) to A.Z.; NWO-VIDI (917.14.374) to L.F.; NWO-VENI (194.006) to D.V.Z.; NWO-VENI (192.029) to M.W.; NWO Spinoza Prize SPI 92–266 to C.W.; the European Research Council (ERC) (FP7/2007–2013/ERC Advanced Grant 2012-322698) to C.W.; ERC Starting grant 637640 to L.F.; ERC Starting Grant 715772 to A.Z.; ERC Consolidator Grant (grant agreement No. 101001678) to J.F.; and RuG Investment Agenda Grant Personalized Health to C.W. MM work is supported by RYC- 2017-22249 and PID2019-107937GA-I00 grants. T.S. holds scholarships from the Junior Scientific Masterclass, University of Groningen[grant no. 17–34]. AR is funded by a Formación Personal Investigador (FPI) grant [grant no. PRE2019-090193]. The Lifelines Biobank initiative has been made possible by a subsidy from the Dutch Ministry of Health, Welfare and Sport; the Dutch Ministry of Economic Affairs; the University Medical Centre Groningen (UMCG, the Netherlands); the University of Groningen and the Northern Provinces of the Netherlands.Peer reviewe

Rheologic changes of hypothermic preserved red blood cells

Jaarlijks ontvangen vele mensen een bloedtransfusie. Tijdens het bewaren van rode bloedcellen (RBCs) in de koelkast treden er veranderingen op in de eigenschappen van de RBCs die de functionaliteit na infusie zouden kunnen beïnvloeden. De reologie van de RBCs speelt hierbij een belangrijke rol, voornamelijk omdat veranderingen in de reologische eigenschappen van RBCs de bloedtoevoer en dus de zuurstof uitwisseling in de microcirculatie zouden kunnen belemmeren. De experimenten beschreven in dit proefschrift hadden als doel de reologische eigenschappen van RBCs te onderzoeken om zo meer inzicht te verkrijgen in de kwaliteit van gepreserveerde RBCs. Daarnaast werd het gebruik van ingevroren RBCs voor transfusie doeleinden onderzocht. We toonden aan dat 200-kDa HES polymeren nuttig zijn om als pro-aggreganten in reologische studies te fungeren. Studies met RBCs die gedurende 5 week bij 2-6°C bewaard werden laten bovendien zien dat de aggregatie en deformabiliteit van RBCs behouden blijven maar dat het ATP gehalte geleidelijk af neemt. Ingevroren RBCs worden beperkt gebruikt in de transfusiegeneeskunde. De beperkte kennis omtrent de kwaliteit van ingevroren RBC speelt hierbij een rol. We tonen aan dat het invriesproces geen nadelige uitwerking heeft op de aggregatie, deformabiliteit en het ATP gehalte van ontdooide RBCs. Een nieuwe Bio-vriezer zou het gebruik van ingevroren RBCs kunnen bevorderen omdat RBCs met slechts 20% glycerol gepreserveerd worden. Studies met humane en ratten RBCs laat zien dat de RBCs die ingevroren zijn met behulp van de Bio-vriezer en opgeslagen zijn in -80°C vriezer, daarvan de integriteit, deformabiliteit en de overlevingsduur tot en met 48 uur na infusie behouden word. De resultaten van dit proefschrift leveren een bijdrage aan de kennis over de kwaliteit van bewaarde RBCs en zouden de toepasbaarheid van ingevroren RBCs kunnen bevorderen. Met name omdat ingevroren RBCs veilig en effectief zijn en ze voldoen aan de internationale richtlijnen. Red blood cell (RBC) transfusions have been practiced worldwide. During refrigerated storage the RBCs undergo various changes that could hamper the RBC to adequately function after infusion. The rheologic properties are important determinants of the quality of RBCs. Particularly because impaired RBC rheological properties, which are enhanced aggregability, reduced deformability and elevated adherence to endothelial cells, proposes a circulatory risk by hindering adequate tissue perfusion and contributing to ischemia or even infarction in the micro-vascular environment. The experiments herein were performed to gain a better understanding of the RBC quality from a rheologic perspective in transfusion medicine, as well as to explore the utilization of cryopreserved RBCs for routine clinical practice. We demonstrate that 200-kDa HES polymers are useful pro-aggregants in RBC rheologic studies. Furthermore, we demonstrated that the aggregability and deformability of RBCs were well preserved during routine blood bank storage, but that the ATP content was gradually declining. In order to circumvent storage induced lesion, cryopreservation of RBCs has been used previously. Yet, the subsequent unfamiliarity with regard to the quality of cryopreserved RBCs has also limited clinical usage. We demonstrated that the freezing procedure did not adversely affect the aggregability, deformability or ATP content of cryopreserved RBCs. Also, the feasibility of a new Bio-freezer was investigated as a way to improve the clinical applicability of cryopreserved RBCs. Usage of the liquid Bio-freezer in combination with the -80°C mechanical freezer, enabled preservation of RBCs with 20% glycerol, while maintaining the RBC integrity, deformability and high 48-hour posttransfusion survival values. The results of this thesis will contribute to knowledge about the quality of stored RBCs and could contribute to expanding the utilization of cryopreserved RBCs in clinical practice. Especially, since cryopreserved RBCs are available, safe and in compliance with international guidelines.

Standardization of incubation conditions for hemolysis testing of biomaterials

Hemolysis testing is the most common method to determine the hemocompatibility properties of biomaterials. There is however no consensus on the procedures of hemolysis testing due to insufficient comparative studies on the quality of the red blood cells used and the experimental conditions of testing. In this study we determined the effects of a number of incubation variables on the sensitivity and reproducibility of the hemolysis test using positively as well as negatively responding biomaterials and compared these results to those obtained according to the American Society for Testing and Materials (ASTM) standard. The ASTM standard method recommends hemolysis testing with highly diluted rabbit blood that is static incubated for 3 h. in this study we found that 24 h incubation of a biomaterial sample at 37 degrees C in slightly diluted human blood or with washed red blood cells was the most sensitive hemolysis test. Moreover usage of cryopreserved human RBC in the hemolysis test seemed to be a good alternative for fresh RBC since cryopreserved and fresh human RBC gave similar results in the hemolysis test. Hemolysis testing by exposing diluted rabbit erythrocytes to biomaterials as according to the ASTM method or by exposing biomaterials extract in saline to washed human red blood cells gave a different outcome and appeared not to be representative for clinical applications. (C) 2009 Elsevier B.V. All rights reserved