title: Molecular and biological hallmarks of ageing.
abstract: BACKGROUND
  Ageing is the inevitable time-dependent decline in physiological organ function that eventually leads to death. Age is a major risk factor for many of the most common medical conditions, such as cardiovascular disease, cancer, diabetes and Alzheimer's disease. This study reviews currently known hallmarks of ageing and their clinical implications.
  
  
  METHODS
  A literature search of PubMed/MEDLINE was conducted covering the last decade.
  
  
  RESULTS
  Average life expectancy has increased dramatically over the past century and is estimated to increase even further. Maximum longevity, however, appears unchanged, suggesting a universal limitation to the human organism. Understanding the underlying molecular processes of ageing and health decline may suggest interventions that, if used at an early age, can prevent, delay, alleviate or even reverse age-related diseases. Hallmarks of ageing can be grouped into three main categories. The primary hallmarks cause damage to cellular functions: genomic instability, telomere attrition, epigenetic alterations and loss of proteostasis. These are followed by antagonistic responses to such damage: deregulated nutrient sensing, altered mitochondrial function and cellular senescence. Finally, integrative hallmarks are possible culprits of the clinical phenotype (stem cell exhaustion and altered intercellular communication), which ultimately contribute to the clinical effects of ageing as seen in physiological loss of reserve, organ decline and reduced function.
  
  
  CONCLUSIONS
  The sum of these molecular hallmarks produces the clinical picture of the elderly surgical patient: frailty, sarcopenia, anaemia, poor nutrition and a blunted immune response system. Improved understanding of the ageing processes may give rise to new biomarkers of risk or prognosis, novel treatment targets and translational approaches across disciplines that may improve outcomes.
authors.affiliation: Gastrointestinal Translational Research Unit, Molecular Laboratory, Stavanger University Hospital, Stavanger, Norway.|Department of Gastrointestinal Surgery, Stavanger University Hospital, Stavanger, Norway.
authors.forename: J R
authors.initials: JR
authors.lastname: Aunan
authors.affiliation: Gastrointestinal Translational Research Unit, Molecular Laboratory, Stavanger University Hospital, Stavanger, Norway.|Department of Gastrointestinal Surgery, Stavanger University Hospital, Stavanger, Norway.
authors.forename: M M
authors.initials: MM
authors.lastname: Watson
authors.affiliation: Gastrointestinal Translational Research Unit, Molecular Laboratory, Stavanger University Hospital, Stavanger, Norway.|Centre for Organelle Research (CORE), Faculty of Science and Technology, University of Stavanger, Stavanger, Norway.
authors.forename: H R
authors.initials: HR
authors.lastname: Hagland
authors.affiliation: Gastrointestinal Translational Research Unit, Molecular Laboratory, Stavanger University Hospital, Stavanger, Norway.|Department of Gastrointestinal Surgery, Stavanger University Hospital, Stavanger, Norway.|Department of Clinical Medicine, University of Bergen, Bergen, Norway.
authors.forename: K
authors.initials: K
authors.lastname: Søreide
mesh_terms: D053687:Adult Stem Cells / Q000502:physiology; D000375:Aging / Q000235:genetics / Q000502:physiology*; D002450:Cell Communication / Q000502:physiology; D016922:Cellular Senescence / Q000502:physiology; D044127:Epigenesis, Genetic / Q000502:physiology; D042822:Genomic Instability / Q000502:physiology; D006801:Humans; D008017:Life Expectancy; D028361:Mitochondrial Diseases / Q000209:etiology; D009747:Nutritional Physiological Phenomena / Q000502:physiology; D057165:Proteostasis Deficiencies / Q000209:etiology; D016615:Telomere / Q000502:physiology