Human liver tissue for research is procured from donated human liver. It is obtained through established clinical or tissue-procurement networks rather than collected directly by a research laboratory. The tissue collection process, that is, consented donors, surgical resections, transplant-relatedRead more
Human liver tissue for research is procured from donated human liver. It is obtained through established clinical or tissue-procurement networks rather than collected directly by a research laboratory.
The tissue collection process, that is, consented donors, surgical resections, transplant-related sources, or accredited tissue banks depends on the research objective and research design. The exact source can vary based on factors such as donor eligibility, tissue quality, availability, and the requirements of the study.
It is crucial to maintain ethical regulations to procure human liver tissue. This involves gaining informed consent and clearance from the relevant ethical committee. Other information including donor age, sex, medical history, and tissue collection details are noted in detail by the researchers.
The type of liver material you need also makes a difference. For example, fresh or cryopreserved liver tissue may be used for histology, molecular studies, or primary hepatocyte isolation. Other researchers may need processed biological models such as human liver microsomes (HLM) or human liver S9 fractions, which are prepared from liver tissue and are commonly used in drug metabolism, ADME, and toxicology studies.
For isolation of the human liver tissue, the tissues are homogenized in an adequate buffer solution maintained at appropriate pH. The tissues are subjected to enzymatic digestion (collagenase or trypsin) to isolate single cells. The digested tissues are mixed with complete culture media and centrifuged to obtain the tissue pellet, which is further seeded in the cell culture flask or plates. The cells are incubated under adequate conditions with a temperature of 37 °C, 5% CO2, and relative humidity.
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Cytosol and S9 fraction are obtained from tissue homogenate. However, they differ widely in their functionality and thus have distinct biomedical research applications. Cytosol is the liquid portion of the cell that remains after removing the nucleus, mitochondria, lysosomes, microsomes, and other mRead more
Cytosol and S9 fraction are obtained from tissue homogenate. However, they differ widely in their functionality and thus have distinct biomedical research applications.
Cytosol is the liquid portion of the cell that remains after removing the nucleus, mitochondria, lysosomes, microsomes, and other membrane-bound organelles through ultracentrifugation. It contains soluble proteins, enzymes, metabolites, and cofactors involved in various cellular processes. Cytosolic preparations are commonly used to study phase II drug metabolism, enzyme activity, signal transduction, and intracellular biochemical pathways.
In contrast, the S9 fraction is produced by centrifuging a tissue homogenate at approximately 9,000 × g, leaving behind a supernatant that contains both the cytosolic components and microsomal vesicles. Because it includes enzymes from both cellular compartments, the S9 fraction supports studies of both phase I and phase II metabolism. It contains important drug-metabolizing enzymes such as cytochrome P450s (from microsomes), along with transferases and other soluble enzymes found in the cytosol.
Based on the research purpose and distinct objective, the cytosol or S9 fraction is chosen. For instance, if the purpose is investigation of the soluble enzymes or intracellular metabolic pathways, cytosol is the preferred preparation. However, when researchers need a broader understanding of drug metabolism, including oxidation, reduction, hydrolysis, and conjugation reactions, the S9 fraction offers a more comprehensive in vitro model.
Thus, cytosol represents soluble intracellular fraction, whereas S9 fraction combines cytosolic and microsomal enzymes.
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