Biomarkers

from Wikipedia, the free encyclopedia

Biomarkers for medicine or biology are measurable parameters of biological processes that have prognostic or diagnostic significance and are therefore used as indicators e.g. B. be used for environmental pollution or diseases .

In geology , biomarkers or biosignatures are organic substances that are contained in sediments and allow conclusions to be drawn about their (biological) origin.

medicine

Biomarkers are characteristic biological features that can be measured objectively and indicate a normal biological or pathological process in the body. A biomarker can be cells, genes, gene products or certain molecules such as enzymes or hormones. Complex organ functions or characteristic changes in biological structures are also used as medical biomarkers.

A distinction is made between disease-related and drug-related biomarkers.

  • The disease-related biomarkers, as so-called risk indicators or predictive biomarkers, provide information on whether a disease is imminent, whether the disease already exists (diagnostic biomarker) or how a disease is likely to develop in individual cases (prognostic biomarker).
  • The drug-related biomarkers show whether and how a drug will work on a specific patient and how his organism will implement it. In addition to long-known parameters such as those recorded in a blood count and measured objectively, there are a large number of new biomarkers in the various medical disciplines.

A reliable diagnosis of the disease is essential, especially in the case of chronic diseases, for the treatment of which the patient may have to take medication with corresponding side effects for years. Biomarkers are becoming more and more important here, because they can confirm a difficult diagnosis or even make it possible in the first place. A number of diseases such as certain cancers , Alzheimer's disease or rheumatoid arthritis are often preceded by an early, asymptomatic stage of the disease. In this phase biomarkers help to identify symptom-free people at risk in a timely and reliable manner.

In order to be able to use a biomarker for diagnostics, the sample material must be as easily accessible as possible. This can be done by the doctor taking a blood sample, a urine or saliva sample or a drop of blood, as every diabetic takes from the fingertip for regular blood sugar self-measurement.

Of course, a biomarker has to be evaluated. The verification procedure must be precise and easy to carry out, whereby the results of the various laboratories must not or only slightly differ from one another. The importance of the biomarker for diagnosis, prognosis and risk assessment of the disease concerned must be proven in independent studies.

ecology

If environmental influences (e.g. solar radiation, lack of water) or foreign substances (e.g. pollutants , pathogens or drugs ) penetrate a biological system, they change the metabolism . This change becomes measurable by determining the activity of characteristic substances, their presence or their amount.

Proteins (e.g. VTG ), carbohydrates , hormones or metabolic products are usually examined as such characteristic substances . A distinction can be made between integral and specific biomarkers. Integral biomarkers can include a variety of substances. Rather, they show a lot of possible deviations. Specific biomarkers, on the other hand, are individual indicators for a specific metabolic step.

Leaves or needles, often also roots, are removed from plants in order to be able to extract the markers. The topic is researched in a wide variety of ways, the origins can be found in ecotoxicology .

In the case of fish stocks, the corpulence factor is used to characterize them and assess biomarker responses.

geology

Biomarker (arrow) in a loess profile, presumably caused by steppe fires

In geology and organic geochemistry , organic substances extracted from sediments that can be traced back to certain organisms are referred to as biomarkers. Due to their structure or their composition, they can give indications of their origin, which can be used as an aid for the reconstruction of climate changes , organisms societies as well as the sedimentary deposition environment in the geological past.

Geochemical biomarkers are primarily lipids ( hydrocarbons , fatty acids , sterols , hopanoids), as these are relatively stable and can also be preserved over geological time. The type of substance can provide information about the original organism (e.g. algae, land plants).

So z. B. certain ketones (alkenones) are produced by certain marine algae , long-chain n- alkanes (with more than 25 carbon atoms) are synthesized in the leaf growths of higher plants. Furthermore, the occurrence of some substances, such as diploptes (bacterial markers; cyanobacteria ), provides information on biological processes at the time the sediment is deposited.

In addition to the structure, the ratio of the stable isotopes of primarily carbon and hydrogen is often measured on these biomarkers in order to obtain information on the origin of the substance. The carbon isotope can e.g. B. Conclusions about biological processes (e.g. photosynthesis ) that allow hydrogen isotopic to climatic influences (e.g. humidity or dryness) at the time of the formation of the substances. If the sediment is changed after its deposition due to the influence of temperature and pressure, relatively stable biomarkers are also changed. You can then no longer necessarily infer the biological starting substance and also speak of geomarkers .

Astrobiology

The term biomarker or biosignature is also used in astrobiology . This refers to gases such as oxygen (O 2 ), ozone (O 3 ), water - especially as water vapor - (H 2 O), carbon monoxide (CO) and methane (CH 4 ), which are based on biological activity, e.g. B. on an exoplanet , could indicate. Using astro spectroscopy , methods can be developed to research the biosignatures of extraterrestrial ecosystems . In 2012, astronomers tested this option with the VLT and analyzed the earth's glow . With future astronomical instruments such as B. the European Extremely Large Telescope , this methodology can also be used to research biosignatures on exoplanets and exomonde .

See also

literature

  • Gerd Schmitz, (et al.): Biomarkers - Importance for medical progress and benefit assessment. Schattauer, Stuttgart 2008, ISBN 978-3-7945-2614-7
  • Kenneth E. Peters, (et al.): The biomarker guide - Biomarkers and isotopes in the environment and human history. Volume 1 & Biomarkers and isotopes in petroleum systems and earth history. Volume 2, Cambridge Univ. Press, Cambridge 2005, ISBN 0-521-78158-2 & ISBN 0-521-83762-6
  • World Health Organization : Biomarkers in risk assessment - validity and validation. WHO, Geneva 2001, ISBN 92-4-157222-1
  • David B. Peakall, Lee R. Shugart: Biomarkers - Research and Application in the Assessment of Environmental Health. Springer, Berlin 1993, ISBN 0-387-54612-X
  • Joseph Seckbach: From fossils to astrobiology - records of life on Earth and the search for extraterrestrial biosignatures. Springer, Dordrecht 2009, ISBN 978-1-402-08836-0 .

Web links

Wiktionary: Biomarker  - explanations of meanings, word origins, synonyms, translations

Individual evidence

  1. ^ R. Craig-Schapiro, AM Fagan, DM Holtzman: Biomarkers of Alzheimer's disease. In: Neurobiology of Disease. Volume 35, number 2, August 2009, pp. 128-140, doi : 10.1016 / j.nbd.2008.10.003 , PMID 19010417 , PMC 2747727 (free full text) (review).
  2. ↑ Egerer K, Feist E, Burmester G: Serological diagnosis of rheumatoid arthritis: Antibodies against citrullinated antigens [The Serological Diagnosis of Rheumatoid Arthritis - Antibodies to citrullinated antigens] . In: Dtsch Arztebl Int 2009; 106 (10): 159-63 . August.
  3. ↑ Karin Bracht: Biomarkers: Indicators for Diagnosis and Therapy . In: Pharmaceutical newspaper online . August.
  4. ↑ VDI 4230 sheet 5: 2018-12 Biological methods for recording environmental pollution (bioindication); Fish as effect indicators (Biological procedures to determine environmental impact (bioindication); Fish as effect indicators). Beuth Verlag, Berlin, p. 40.
  5. ↑ "Recently, astrobiologists have adopted the term biomarker and its definition has been extended. Today the word" biomarker "is no longer used exclusively for organic material but is used for any evidence that indicates present or past life detected either in situ or remotely. " in: Iain Gilmour, et al .: An introduction to astrobiology. , Cambridge Univ. Press, Cambridge 2004, ISBN 0-521-83736-7 , p. 13.
  6. ↑ Determine how to recognize signatures of life on other worlds and on early Earth ( Memento of the original dated December 10, 2010 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. @ astrobiology.arc.nasa.gov; Biosignature @ en.wikipedia (accessed October 18, 2010) @1@ 2Template: Webachiv / IABot / astrobiology.arc.nasa.gov
  7. ↑ DJ Des Marais, MO Harwit, KW Jucks, JF Kasting, DN Lin, JI Lunine, J. Schneider, S. Seager, WA Traub, NJ Woolf: Remote sensing of planetary properties and biosignatures on extrasolar terrestrial planets. In: Astrobiology. Volume 2, Number 2, 2002, pp. 153-181, doi : 10.1089 / 15311070260192246 , PMID 12469366 .
  8. ^ Arnold Hanslmeier: Biomarkers on Extrasolar Planets. In: ebender: Habitability and cosmic catastrophes. Springer, Berlin 2009, ISBN 978-3-540-76944-6 , pp. 196ff. " Typical biomarkers are the gases O 2 , O 3 , H 2 O, CO, CH 4. They indicate the existence of living organisms (past or present). " ( Limited preview in Google book search).
  9. ↑ Astronomers "discovered" life on earth science.orf.at; "Alien Moons Could Act as Giant Mirrors to Reveal Signs of Organic Life" --The ESO dailygalaxy.com, accessed March 2, 2012
  10. ↑ Michael F. Sterzik, et al .: Biosignatures as revealed by spectropolarimetry of Earthshine. Nature, 483, 64-66, (01 March 2012), doi : 10.1038 / nature10778
  11. ^ VLT Rediscovers Life on Earth eso.org, accessed March 2, 2012.