November 29, 2022

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​What is preclinical in vitro and in vivo research?

​What is preclinical in vitro and in vivo research?

​What is preclinical in vitro and in vivo research?  Before testing candidate drugs in humans, their safety and efficacy (effectiveness) must be explored in preclinical studies. These studies can be “in vitro”, which means “in a container” in Latin, which refers to research using cell culture in vitro, or “in vivo”, which means “in vivo” in Latin. Refers to the research conducted inside the body.

In pre-clinical research, it is also necessary to use animals for in vivo testing, because this stage must be carried out before human testing to ensure its safety.
​What is preclinical in vitro and in vivo research?



In vitro

In order to conduct in vitro studies, the cell lines used are derived from human or non-human animals and are introduced into new drugs under development in petri dishes or test tubes. In vitro research has many benefits. The first and most obvious benefit is that they will not cause harm to animals or humans derived from cell cultures, and they do not have the disadvantages of animal testing. Other benefits of in vitro models include relatively inexpensive operation and operation. They are also reliable and efficient, and can produce reliable results.

However, although in vitro studies provide many significant benefits, they have a major disadvantage. In vitro studies are limited because they cannot mimic how pharmaceutical compounds interact with all the molecules and cell types present in complex organs. They can only be tested individually, and the human body is a dynamic environment in which many pathways and cells are in constant exchange and communication. This may make in vitro studies difficult to predict the complexity of potential interactions.

Despite this limitation, in vitro research is still a key part of preclinical research. Here, we will take the in vitro testing of new cancer therapeutics in preclinical research as an example to illustrate how in vitro research can move forward and how technology can be developed to overcome the limitations of in vitro research.

Historically, preclinical in vitro cancer models have faced the drawback of not being able to reliably predict the prognosis of patients. Although in vitro testing in cell-based models has always been a fundamental part of cancer research, these preclinical studies have not always been able to successfully generate data reflecting the exact behavior of malignant tumors on drug candidates.

To solve this problem, scientists are working hard to develop the techniques used in these experiments. In particular, there is now a more complex co-cultivation technology-based technology based on living cells in vitro.

In recent decades, we have seen the transition from two-dimensional cell culture to three-dimensional cell growth. This emerging technology can capture the physiological environment more effectively and better reflect the growth mode of tumor tissue. This new technology can provide a three-dimensional structure and preserve the heterogeneity of tumor cells observed in vitro. Compared with two-dimensional cell culture, it is more able to prove the complex microenvironment and surrounding matrix composition.


In vivo

Compared with in vitro, in vivo research is carried out in living organisms. In preclinical trials, these trials take place in animal subjects. In clinical trials, in vivo studies can use humans or animals as subjects.

In vivo studies can address the limitations of in vitro studies. They can prove the effect of a drug on the entire body, not how it affects isolated cells. This allows in vivo studies to better visualize potential interactions, which can improve their predictions of safety, toxicity, and efficacy. This helps scientists predict the impact of candidate drugs on human diseases.

However, although in vivo studies solve the disadvantages of in vitro studies, they also have their own limitations. In vivo research faces major ethical issues, especially for preclinical research that only allows animal models to be tested. Debates about the ethics of animal testing have intensified for decades.

At present, regulations and laws related to animal testing are becoming more and more stringent. It is hoped that scientists who conduct preclinical studies on animals will conduct preclinical in vivo studies to prove that there is no alternative method for conducting experiments. They are also required to show a sense of balance, that the benefits of research (the knowledge gained) outweigh the disadvantages (the pain caused to animals).

Like in vitro research, in vivo research is also undergoing technological transformation. Emerging technologies such as CRISPR will make the execution of complex animal models easier, cheaper and faster.

Although in vivo studies face major ethical considerations, they are likely to remain an essential part of preclinical research. The future is expected to bring significant advancements in preclinical technology, both in vitro and in vivo, which should facilitate more accurate data collection, as well as faster and simpler methods. These advances are expected to improve the quality of preclinical data and reduce reliance on traditional animal models.

(source:internet, reference only)

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