in the alveoli during respiratory movement. In fact, the mechanical forces increased

tissue permeability three times over that time in combination with IL-2. Additional

research revealed that IL-2 successfully inhibited vascular leakage completely when

given with angiotensin-1 (Xu et al. 2013).

The ‘lung-on-a-chip’ model for asthma and chronic obstructive pulmonary dis-

ease (COPD) was used to substantiate claims that tofacitinib, a medication employed

to treat rheumatoid arthritis, could suppress lung inflammation. Additionally, it was

discovered that inhibiting neutrophil adhesion with a bromodomain-containing

protein 4 (BRD4) inhibitor could reduce lung infection by nearly 75% under

complex flow conditions (Benam et al. 2016).

6.6.2

Liver-on-a-Chip

The liver has a multitude of roles, such as protein synthesis, hormonal balance,

glycogen storage, and detoxification. It is an important toxicity target in human drug

interactions as well as a player in the drug induction. The liver is extremely active in

metabolism and thus essential to life. Metabolic activity in the liver is very high, and

without it, we would not have a metabolism. Besides its amazing regenerative

capabilities, chronic diseases and viral infections cause significant damage to tissue,

as well. Hepatocytes are tied together by blood vessels and Kupffer cells into the

hepatic lobule, which performs all the major functions of the liver. Hepatocytes are

difficult to keep alive in the lab. Hepatic cell microsphere system was specifically

created to study hepatic interactions in 3D cultures. Other experimentation that may

be conducted includes but is not limited to drug testing, pathogenesis, human

physiology, and toxicity, and screening with a liver-on-chip (Dixon et al. 2018).

The liver is used in human and animal models to study the metabolic rate and

toxicity of chemicals and medications, as well as to assess the efficacy of treatments.

Primary cells are obtained from patients or cell banks, such as the ‘American Tissue

Culture Collection’, and subjected to a battery of tests to determine whether they

exhibit the properties of human tissue when cultured. They may use cell cultures to

better understand how drugs move through the body. The ability to discover new

drugs is harmed when normal human liver cell activities such as transport and drug

breakdown are lost in cell culture. Liver-on-chip systems have been proposed as a

new generation of in vitro drug screening models. Some liver-on-chip systems

include biophysically preprefigured or 3D bio-printed matrices to enable 3D organ

building (Bhatia and Ingber 2014; Miranda et al. 2021).

On the one hand, hepatology research and drug discovery depend on in vitro

models of the liver. An essential part of these models is the cell source. Human,

animal-derived, and hep-derived stem cells are the three major cell types employed

to generate real liver tissue in the laboratory. Researchers currently utilise a variety

of human hepatic cell outlines like hepatocytes, sinusoidal endothelial (Hep2), and

hepatic stem cells for toxicological assessments (HepaRG). Hepatocytes are the

liver’s parenchymal cells that help maintain liver functions, making them the most

active cells in the lobules. Also known as the reticuloendothelial, the system, the

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