Biomarker

Biomarkers for medicine or biology are measurable products of organisms that are used as indicators eg for environmental pollution or disease.

In geology is meant by biomarkers organic substances that are contained in sediments, and allow conclusions to their ( biological ) origin.

Medicine

Biomarkers are characteristic biological characteristics that can be objectively measured and can point in the body to a normal biological or pathological process.

For a biomarker can be cells, genes, gene or specific molecules, such as enzymes or hormones. Even complex organ functions or characteristic changes in biological structures are used as medical biomarkers.

As catchy as the blood picture may be mentioned, which gives vital clues on the health of the patient from the hemoglobin or blood sugar levels.

In recent years is observed a growing interest in the pharmaceutical industry in the exploration of biomarkers. Thus, according to a recent market research study, the number of clinical trials with biomarkers has increased by 10 times in just the past four years. According to estimates by the pharmaceutical industry today invests annually up to two billion euros in biomarker research. Reasons for this trend are to look for a sharp decline in the number of newly approved drugs. On the other hand many complex diseases, such as AIDS or cancer, despite intensive research efforts to date still not sufficiently - and / or late (too) - diagnosable or even treatable. Other diseases are to be determined only very costly and / or time consuming with traditional methods. For example, with reasonable certainty distinguish a mood of depression, a psychologist only after extensive psychological interviews. A biomarker - ie a blood test to detect depression - is under investigation. Great hopes are therefore put into the research and development of novel biomarkers that are made ​​accessible using novel techniques such as genome sequencing, proteomics and DNA microarrays (to be).

Disease-related and drug- related biomarkers

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

  • The disease-related biomarkers provide a so-called risk indicator or predictive biomarker information about whether threatening disease, whether the disease already exists ( diagnostic biomarkers ) or how a disease is likely to develop in the individual case ( prognostic biomarkers).
  • The drug-related biomarkers indicate whether and how a drug in a particular patients and act as the organism will implement it. In addition to long-known parameters such as they are, for example, detected in a blood count and measured objectively, there are in the various medical disciplines, a variety of novel biomarkers.

The "classical " biomarkers for medicine is a laboratory parameter that the doctor using it as a decision support for the diagnosis and treatment decision. For example applies the rheumatoid factor detection has long been an important diagnostic marker for rheumatoid arthritis.

In addition to the rheumatoid factors in the diagnosis and treatment of rheumatoid arthritis ( RA) and modern biomarkers such as antibodies against the body's own citrullinated proteins, the so-called ACPAs an important role. These biomarkers can be detected before the first symptoms of rheumatic disease in the blood and are thus valuable and very meaningful biomarkers for the diagnosis of this autoimmune disease. In addition, they point to an impending severe course of the disease with severe bone and joint destruction, making them available to the physician as an important tool in the early diagnosis and rapid treatment decision.

Another often -studied biomarker is prostate specific antigen (PSA ) as it ( prostate cancer) are extremely useful in the detection of malignant diseases of the prostate. Also, the prostate-specific membrane antigen (PSMA ) correlates with the disease stage of prostate cancer and is mentioned in the literature.

Requirements for a biomarker of Medicine

Especially in chronic diseases, their treatment, the patient may need to take medications for years with appropriate side-effects, a reliable diagnosis of the disease is essential. Here biomarkers win more and more important, because they can protect a difficult diagnosis, or even possible at all. A number of disorders such as certain cancers, Alzheimer's disease or rheumatoid arthritis is often preceded by an early, asymptomatic stage of the disease -free. In this phase, biomarkers help to identify asymptomatic persons at risk on time and reliable.

To use a biomarker for the diagnosis, the sample material must be as easily accessible. This can be done about a blood collection by the doctor, a urine or saliva sample, or a drop of blood, as every diabetic himself takes him for regular blood glucose self- measurement itself from the fingertip.

For the rapid initiation of therapy is important, how quickly the result of the Biomarkernachweis present. Optimal here is a quick test that returns the result after a few minutes, which the treating physician provides a quick start of therapy.

Of course, a biomarker must be evaluated. The detection method must be accurate and easy to perform, and the results of the different laboratories may not or only slightly different. The importance of biomarkers for diagnosis, prognosis and risk assessment of the complaint must be in independent studies.

Ecology

If environmental influences (eg solar radiation, water shortage) or entry of foreign matter ( pollutants, pathogens or drugs, for example ) in a biological system, they alter the metabolism. This change is measured by the activity of representative compounds whose presence or amount thereof is determined.

As such typical compounds are usually proteins studied ( for example, DEF ), carbohydrates, hormones or metabolites. It is possible to distinguish between integral and specific biomarkers. Integral biomarkers can include a variety of substances. They indicate rather a set of possible deviations. Specific biomarkers, however, are individual counters for a specific metabolic step.

When plants are leaves or needles, often roots, taken in order to extract the marker can. The topic is researched very diverse, its origins can be found in ecotoxicology in Tharandt, which belongs to the Technical University of Dresden.

Geology

In geology and organic geochemistry of sediments are derived from organic substances that can be traced back to certain organisms, referred to as biomarkers. Due to their structure or their composition, they may provide clues to their origin, which can be used as an aid for the reconstruction of climate changes, organisms Socialization and the sedimentary depositional environment in the geological past. Geochemical Biomarkers are mainly lipids (hydrocarbons, fatty acids, sterols, hopanoids ), since these are relatively stable and can remain even over geological time. The nature of the substance may give statements about the origin organism ( eg algae, land plants ). For example, certain ketones ( alkenones ) produced by certain marine algae, long-chain n- alkanes ( of more than 25 carbon atoms) are synthesized in the leaf growth of higher plants. Furthermore, the appearance of some substances, such as Diplopten ( bacterial markers; cyanobacteria ) are indications of biological processes at time of deposition of the sediment. In addition to the structure, the ratio of stable isotopes of carbon and hydrogen in particular is often measured on these biomarkers to obtain information on the origin of the substance. The Kohlenstoffisotopie can allow, for example, to draw conclusions about biological processes (eg, photosynthesis), the Wasserstoffisotopie to climatic influences (eg humidity or dryness) at the time of formation of the substances. The sediment is changed after its deposition by the influence of temperature and pressure, and relatively stable changes are biomarkers. You can then no longer necessarily indicative of the biological starting material, and also speaks of Geomarkern.

Astrobiology

Also in astrobiology, the term biomarker or biosignature used. This refers to gases such as oxygen (O2 ), ozone (O3 ), water - especially as water vapor - (H2O), carbon monoxide (CO ) and methane (CH4), the biological activity, eg could be on an exoplanet, point. Using spectropolarimetry could methods are developed to detect biosignatures of extraterrestrial ecosystems. 2012 astronomers tested this possibility with the VLT and analyzed the earthshine. With future astronomical instruments, such as eg the European Extremely Large Telescope, this methodology for the study be applied to exoplanets and Exomonde for biosignatures.

126610
de