{{short description|Process of testing biological interventions on whole, living organisms}} {{italic title}} {{other uses|In Vivo (disambiguation)}} thumb|right |A laboratory rat with a brain implant, that was used to record ''in vivo'' neuronal activity Studies that are '''''in vivo''''' (Latin for "within the living"; often not italicized in English<ref name="MWCD">{{Citation | author = Merriam-Webster | author-link = Merriam-Webster | title = Merriam-Webster's Collegiate Dictionary | publisher = Merriam-Webster | url = http://unabridged.merriam-webster.com/collegiate/ | postscript = . | access-date = 2014-04-20 | archive-date = 2020-10-10 | archive-url = https://web.archive.org/web/20201010163505/https://unabridged.merriam-webster.com/subscriber/login?redirect_to=%2Fcollegiate%2F }}</ref><ref name="AMA10section12.1.1">{{cite book |veditors=Iverson C, Flanagin A, Fontanarosa PB, Glass RM, Gregoline B, Lurie SJ, Meyer HS, Winker MA, Young RK |title=AMA Manual of Style |edition=10th |publisher=Oxford University Press |location=Oxford, Oxfordshire |year=2007 |isbn=978-0-19-517633-9 |section=12.1.1 Use of Italics |url-access=registration |url=https://archive.org/details/amamanualofstyle0000unse }}</ref><ref>{{Citation |author=American Psychological Association |author-link=American Psychological Association |year=2010 |title=The Publication Manual of the American Psychological Association |edition=6th |location=Washington, DC|publisher=APA |isbn=978-1-4338-0562-2 |section=4.21 Use of Italics }}</ref>) are those in which the effects of various biological entities are tested on whole, living organisms or cells, usually animals, including humans, and plants, as opposed to a tissue extract or dead organism.
Examples of investigations ''in vivo'' include: the pathogenesis of disease by comparing the effects of bacterial infection with the effects of purified bacterial toxins; the development of non-antibiotics, antiviral drugs, and new drugs generally; and new surgical procedures. Consequently, animal testing and clinical trials are major elements of ''in vivo'' research. ''In vivo'' testing is often employed over ''in vitro'' because it is better suited for observing the overall effects of an experiment on a living subject. In drug discovery, for example, verification of efficacy ''in vivo'' is crucial, because ''in vitro'' assays can sometimes yield misleading results with drug candidate molecules that are irrelevant ''in vivo'' (e.g., because such molecules cannot reach their site of ''in vivo'' action, for example as a result of rapid catabolism in the liver).<ref name="pmid26281720">{{cite journal | vauthors = Atanasov AG, Waltenberger B, Pferschy-Wenzig EM, Linder T, Wawrosch C, Uhrin P, Temml V, Wang L, Schwaiger S, Heiss EH, Rollinger JM, Schuster D, Breuss JM, Bochkov V, Mihovilovic MD, Kopp B, Bauer R, Dirsch VM, Stuppner H | display-authors = 6 | title = Discovery and resupply of pharmacologically active plant-derived natural products: A review | journal = Biotechnology Advances | volume = 33 | issue = 8 | pages = 1582–1614 | date = December 2015 | pmid = 26281720 | pmc = 4748402 | doi = 10.1016/j.biotechadv.2015.08.001 }}</ref>
The English microbiologist Professor Harry Smith and his colleagues in the mid-1950s found that sterile filtrates of serum from animals infected with ''Bacillus anthracis'' were lethal for other animals, whereas extracts of culture fluid from the same organism grown ''in vitro'' were not. This discovery of anthrax toxin through the use of ''in vivo'' experiments had a major impact on studies of the pathogenesis of infectious disease.
The maxim ''in vivo veritas'' ("in a living thing [there is] truth")<ref name=veritas>{{cite journal |url=https://www.science.org/doi/10.1126/science.316.5832.1763 |title=Life Science Technologies, Cell Signaling: In Vivo Veritas |journal=Science Magazine |year=2007 |doi=10.1126/science.316.5832.1763 |access-date=2023-12-11|url-access=subscription }} (This citation describes a setup involving two kinds of transgenic mice.)</ref> is a play on ''in vino veritas'', ("in wine [there is] truth"), a well-known proverb.
== Levels of closeness to the natural state == Latin phrases used to describe the closeness of a wet lab experiment setup to the natural state include: * ''In natura'' ("in nature"), the exact natural state<ref>{{Cite journal | last1 = Quintana-Murci | first1 = L. | last2 = Alcaïs | first2 = A. | last3 = Abel | first3 = L. | last4 = Casanova | first4 = J. L. | title = Immunology in natura: Clinical, epidemiological and evolutionary genetics of infectious diseases | doi = 10.1038/ni1535 | journal = Nature Immunology | volume = 8 | issue = 11 | pages = 1165–1171 | year = 2007 | pmid = 17952041 }}</ref> * ''In vivo'' ("in the living"), with a living being (usually the whole organism, in a controlled environment)<ref name=Maroli/> * ''Ex vivo'' ("out of the living"), with part of a living being (usually tissues, organs, or cells)<ref name="Makdisi_etal">{{cite journal |last1=Makdisi |first1=G |last2=Makdisi |first2=T |last3=Jarmi |first3=T |last4=Caldeira |first4=CC |title=Ex vivo lung perfusion review of a revolutionary technology |journal=Annals of Translational Medicine |date=2017 |volume=5 |issue=17 |page=343 |doi=10.21037/atm.2017.07.17 |doi-access=free |pmid=28936437 |pmc=5599284 }}</ref><ref>{{cite journal |last=Griffiths |first=John R. |title=Magnetic resonance spectroscopy ex vivo: A short historical review |journal=NMR in Biomedicine |date=2022 |volume=35 |issue=4 |article-number=e4740 |doi=10.1002/nbm.4740 |pmid=35415860 }}</ref><ref name=Maroli>{{cite journal |last1=Maroli |first1=Amith Sadananda |last2=Powers |first2=Robert |title=Closing the gap between in vivo and in vitro omics: using QA/QC to strengthen ex vivo NMR metabolomics |journal=NMR in Biomedicine |date=2023 |volume=36 |issue=4 |article-number=e4594 |doi=10.1002/nbm.4594 |pmid=34369014 |pmc=8821733 }}</ref> * ''In vitro'' ("in the glass"), usually either a cell culture or a mixture of sub-cellular components (disrupted cell, purified biomolecules)
Different subfields of biology have a tendency to use each word differently. Notable variations from the above include: * Toxicologists lump ''ex vivo'' into ''in vitro'': any data not obtained using a whole animal is ''in vitro''.<ref>{{Cite web |title=In vitro methods - ECHA |url=https://echa.europa.eu/support/registration/how-to-avoid-unnecessary-testing-on-animals/in-vitro-methods |access-date=2023-04-11 |website=echa.europa.eu |language=en-GB}}</ref><ref>{{cite web |last1=Toxicity |first1=National Research Council (US) Subcommittee on Reproductive and Developmental |title=Experimental Animal and In Vitro Study Designs |url=https://www.ncbi.nlm.nih.gov/books/NBK222201/ |website=Evaluating Chemical and Other Agent Exposures for Reproductive and Developmental Toxicity |publisher=National Academies Press (US) |language=en |date=2001}}</ref> * Molecular biologists working on single-celled organisms may refer to a living microbe culture as ''in vivo'', reserving ''in vitro'' for cell-free systems.<ref>{{cite journal |last1=Watson |first1=JF |last2=García-Nafría |first2=J |title=In vivo DNA assembly using common laboratory bacteria: A re-emerging tool to simplify molecular cloning. |journal=The Journal of Biological Chemistry |date=18 October 2019 |volume=294 |issue=42 |pages=15271–15281 |doi=10.1074/jbc.REV119.009109 |doi-access=free |pmid=31522138 |pmc=6802500}}</ref><ref>{{cite journal |last1=Zhou |first1=Xiaojuan |last2=Zhang |first2=Niubing |last3=Gong |first3=Jie |last4=Zhang |first4=Kaixiang |last5=Chen |first5=Ping |last6=Cheng |first6=Xiang |last7=Ye |first7=Bang-Ce |last8=Zhao |first8=Guoping |last9=Jing |first9=Xinyun |last10=Li |first10=Xuan |title=In vivo assembly of complete eukaryotic nucleosomes and (H3-H4)-only non-canonical nucleosomal particles in the model bacterium Escherichia coli |journal=Communications Biology |date=14 November 2024 |volume=7 |issue=1 |doi=10.1038/s42003-024-07211-4|pmid=39543208 |pmc=11564532 }}</ref> * There are also cases of mammalian cell cultures being referred to as ''in vivo''.<ref>{{cite journal |last1=Dettmer |first1=Ulf |last2=Newman |first2=Andrew J. |last3=Luth |first3=Eric S. |last4=Bartels |first4=Tim |last5=Selkoe |first5=Dennis |title=In Vivo Cross-linking Reveals Principally Oligomeric Forms of α-Synuclein and β-Synuclein in Neurons and Non-neural Cells |journal=Journal of Biological Chemistry |date=March 2013 |volume=288 |issue=9 |pages=6371–6385 |doi=10.1074/jbc.M112.403311|doi-access=free |pmid=23319586 |pmc=3585072 }}</ref><ref name="Minde_2020">{{cite journal | vauthors = Minde DP, Ramakrishna M, Lilley KS | title = Biotin proximity tagging favours unfolded proteins and enables the study of intrinsically disordered regions | journal = Communications Biology | year = 2020 | volume = 3 | issue = 1 | page = 38 | doi = 10.1038/s42003-020-0758-y | pmid = 31969649 | pmc = 6976632 | doi-access = free |biorxiv= 10.1101/274761}}</ref>
==Methods of use== According to Christopher Lipinski and Andrew Hopkins, "Whether the aim is to discover drugs or to gain knowledge of biological systems, the nature and properties of a chemical tool cannot be considered independently of the system it is to be tested in. Compounds that bind to isolated recombinant proteins are one thing; chemical tools that can perturb cell function another; and pharmacological agents that can be tolerated by a live organism and perturb its systems are yet another. If it were simple to ascertain the properties required to develop a lead discovered ''in vitro'' to one that is active ''in vivo'', drug discovery would be as reliable as drug manufacturing."<ref>{{cite journal | vauthors = Lipinski C, Hopkins A | title = Navigating chemical space for biology and medicine | journal = Nature | volume = 432 | issue = 7019 | pages = 855–61 | date = December 2004 | pmid = 15602551 | doi = 10.1038/nature03193 | bibcode = 2004Natur.432..855L | s2cid = 4416216 }}</ref> Studies on ''In vivo'' behavior, determined the formulations of set specific drugs and their habits in a Biorelevant (or Biological relevance) medium.<ref>{{cite journal | vauthors = Klein S | title = The use of biorelevant dissolution media to forecast the in vivo performance of a drug | journal = The AAPS Journal | volume = 12 | issue = 3 | pages = 397–406 | date = September 2010 | pmid = 20458565 | pmc = 2895438 | doi = 10.1208/s12248-010-9203-3 }}</ref>
== See also == {{wiktionary}}
* ''In ovo'' * ''In papyro'' * ''In silico'' * ''In simulacra'' * ''In situ'' * ''In utero'' * ''In vivo'' imaging * Vivisection
== References == {{Reflist|30em}}
{{Medical research studies}} {{Research methods in biology}}
Category:Latin biological phrases Category:Animal test conditions