Name: Isolation and Cryopreservation of Human Peripheral Blood Mononuclear Cells for Bioenergetic Studies
Uploaded: 2023-10-20T13:30:00
Description: Watch this Scientific Journal Video about Isolation and Cryopreservation of Human Peripheral Blood Mononuclear Cells for Bioenergetic Studies at JoVE.com

isolation and cryopreservation of human peripheral blood mononuclear cells for bioenergetic studies

PBMC Collection and Cryostorage for Mitochondrial Bioenergetics Analysis

Human peripheral blood mononuclear cells (PBMCs) are used for various applications in many scientific fields, including the study of immunological and bioenergetic issues, such as those related to aging processes or degenerative diseases1,2. PBMCs are heterogeneous in composition and consist of lymphocytes (B cells, T cells, and NK cells), monocytes, and dendritic cells. The cells sometimes show great individual differences and variations within a subject, so standardized procedures for handling these cells are required. Important parameters such as viability and purity of the isolation are the basic requirements for its handling and are additionally influenced by environmental factors such as the time of collection, the melatonin level, whether the subject is fasting, and others3,4.
Based on studies on bioenergetics of PBMCs, we describe here a method for the isolation, cryopreservation, and cultivation of PBMCs that is suitable for other methods as well. While muscle biopsy is considered the gold standard for mitochondrial energy metabolism5, the examination of blood cells is a rapid, minimally invasive procedure. In addition to this, more and more studies suggest that the changes in mitochondrial function in aging and Alzheimer&#39;s disease (AD) occur not only in the brain but also in the periphery6,7,8,9,10. The method also allows investigations of other conditions and diseases, including diabetes mellitus and obesity11,12,13. Gene expression patterns in multiple sclerosis patients can be analyzed, or immune function and influences on it in general14,15,16.
PBMCs generally rely on oxidative phosphorylation (OXPHOS) to generate adenosine triphosphate (ATP)17,18. Therefore, PBMCs cover a wide range of applications as surrogates. In previous reports, the energy metabolism of PBMCs has been used to address organ dysfunctions, such as in early heart failure19, septic shock20 or sex-associated differences4 in mitochondrial function. A generalized method for cryopreservation isolation and cultivation of PBMCs would have advantages in the comparability of results obtained at different institutes. There is a great deal of variation in the protocols for each step21,22, the goal of this method is to provide a guideline for bioenergetic measurements in PBMCs.
In this article we describe a method for measuring bioenergetic parameters in PBMCs. We explain the methods for isolating, cryopreserving and measuring bioenergetics of PBMCs from human blood. This method can be used to determine bioenergetic parameters in patients and evaluate them in a clinical context. To apply these measurements, researchers need access to a patient population from which fresh blood samples can be obtained.

Author Spotlight: Preservation of Bioenergetic Parameters in Peripheral Blood Mononuclear Cells After Cryopreservation 

Cryopreservation and Bioenergetic Evaluation of Human Peripheral Blood Mononuclear Cells

With the help of this method, we want to describe a procedure which is suitable to cryopreserve PBMCs in such a way that after thawing, the bioenergetic parameters are unchanged. One of the major experimental challenges of cryopreservation is that the freezing and thawing process can damage PBMCs, which affects the following bioenergetic measurements. With our protocol, we try to show a way to preserve PBMCs reliably without damage to the cells so that the measured bioenergetic parameters are not influenced.The possibility of preserving PBMCs allows samples to be collected from different centers and measured at one location. It also makes measurement more time independent. Cryopreservation of PBMCs allows studies to be performed simultaneously at multiple sites where the cells are collected and preserved.The collected samples can then be measured centrally. This streamlines the process and planning of studies.

Watch this Scientific Journal Video about Isolation and Cryopreservation of Human Peripheral Blood Mononuclear Cells for Bioenergetic Studies at JoVE.com

Isolation and Cryopreservation of Human Peripheral Blood Mononuclear Cells for Bioenergetic Studies  

To begin, add eight milliliters of DPBS into a sterile 50 milliliter conical tube. To this, add eight milliliters of blood and use a three milliliter plastic Pasteur pipette to mix the contents well. Add 15 milliliters of lymphocyte isolation medium into another conical tube.Tilt the tube by 20 to 30 degrees. Then use a three milliliter Pasteur pipette to apply the first layer of the blood DPBS mix gently over the isolation medium. Layer the remaining mixture carefully over the sidewall of the tube.Slowly bring the tube into an upright position to layer the remaining blood onto the blood layer. Centrifuge the tube at 1000G for 10 minutes at room temperature in a swinging bucket with the brakes off. The blood PBMC mix will separate into four distinct layers.With a Pasteur pipette, remove two thirds of the plasma layer, then use a one milliliter pipette to collect the PBMCs. Transfer the PBMCs into a new 50 milliliter tube until the entire layer has been harvested. Then make the volume up to 25 milliliters with DPBS to remove residual isolation medium and other residues.Centrifuge the tube at 100G for 10 minutes at room temperature with the brakes on. Then remove the supernatant with a vacuum pump. Next, resuspend the pellet in one milliliter DPBS and add more DPBS to make up the volume to 25 milliliters to wash and resuspend the pellet.Cool a freezing container to four degrees celsius. Then place fetal bovine serum on ice. Resuspend the cell pellet containing the isolated PBMCs in one milliliter of fetal bovine serum.Next mixed DMSO with cooled serum on ice at a ratio of one to five. Transfer the cell suspension to two milliliter labeled cryotubes, using one tube per collection tube. With an automated cell counter, determine the cell count and viability.Use a one milliliter pipette to drop one milliliter of the DMSOFBS mixture into the tube. Then place the tubes in the pre-cooled freezing container. Place the container in a freezer at minus 80 degrees Celsius for 24 hours.The next day, remove the tubes from the freezer and store them in the gas phase of liquid nitrogen. Cell counts and viability were consistent before and after cryo-preservation indicating successful isolation and preservation.

Research

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Immunology and Infection

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