Blood plasma fractionation are the general processes separating the various components of

blood plasma Blood plasma is a light Amber (color), amber-colored liquid component of blood in which blood cells are absent, but which contains Blood protein, proteins and other constituents of whole blood in Suspension (chemistry), suspension. It makes up ...

, which in turn is a component of blood obtained through blood fractionation. Plasma-derived immunoglobulins are giving a new narrative to healthcare across a wide range of autoimmune inflammatory diseases.

Blood plasma

Blood plasma Blood plasma is a light Amber (color), amber-colored liquid component of blood in which blood cells are absent, but which contains Blood protein, proteins and other constituents of whole blood in Suspension (chemistry), suspension. It makes up ...

is the liquid component of whole blood, and makes up approximately 55% of the total blood volume. It is composed primarily of water with small amounts of minerals, salts, ions, nutrients, and proteins in solution. In whole blood, red blood cells, leukocytes, and platelets are suspended within the plasma.

Plasma proteins

Plasma contains a large variety of proteins including albumin, immunoglobulins, and clotting proteins such as fibrinogen.Brodniewicz-Proba, T. 1991. "Human Plasma Fractionation and the Impact of New Technologies on the Use and Quality of Plasma-derived Products". ''Blood Reviews''. Vol. 5. pp. 245–57. Albumin constitutes about 60% of the total protein in plasma and is present at concentrations between 35 and 55 mg/mL.Shen, Y., Jacobs, J. M., et al. 2004. "Ultra-High-Efficiency Strong Cation Exchange LC/RPLC/MS/MS for High Dynamic Range Characterization of the Human Plasma Proteome". ''Anal Chem.'' Vol. 76. pp. 1134–44. It is the main contributor to

osmotic pressure Osmotic pressure is the minimum pressure which needs to be applied to a Solution (chemistry), solution to prevent the inward flow of its pure solvent across a semipermeable membrane. It is also defined as the measure of the tendency of a soluti ...

of the blood and it functions as a carrier molecule for molecules with low water

solubility In chemistry, solubility is the ability of a chemical substance, substance, the solute, to form a solution (chemistry), solution with another substance, the solvent. Insolubility is the opposite property, the inability of the solute to form su ...

such as lipid-soluble

hormone A hormone (from the Ancient Greek, Greek participle , "setting in motion") is a class of cell signaling, signaling molecules in multicellular organisms that are sent to distant organs or tissues by complex biological processes to regulate physio ...

enzyme An enzyme () is a protein that acts as a biological catalyst by accelerating chemical reactions. The molecules upon which enzymes may act are called substrate (chemistry), substrates, and the enzyme converts the substrates into different mol ...

fatty acids In chemistry, in particular in biochemistry, a fatty acid is a carboxylic acid with an aliphatic chain, which is either saturated or unsaturated. Most naturally occurring fatty acids have an unbranched chain of an even number of carbon atoms, ...

, metal ions, and pharmaceutical compounds.Matejtschuk, P., Dash, C.H., and Gascoigne, E.W. 2000. "Production of human albumin solution: a continually developing colloid". ''British Journal of Anaesthesia''. Vol 85. pp. 887–95. Albumin is structurally stable due to its seventeen disulfide bonds and unique in that it has the highest water solubility and the lowest isoelectric point (pI) of the plasma proteins. Due to the structural integrity of albumin it remains stable under conditions where most other proteins denature.

Plasma proteins for clinical use

Many of the proteins in plasma have important therapeutic uses. Albumin is commonly used to replenish and maintain blood volume after traumatic injury, during

surgery Surgery is a medical specialty that uses manual and instrumental techniques to diagnose or treat pathological conditions (e.g., trauma, disease, injury, malignancy), to alter bodily functions (e.g., malabsorption created by bariatric surgery s ...

, and during plasma exchange. Since albumin is the most abundant protein in the plasma its use may be the most well known, but many other proteins, although present in low concentrations, can have important clinical uses. See table below.

Plasma processing

When the ultimate goal of plasma processing is a purified plasma component for injection or transfusion, the plasma component must be highly pure. The first practical large-scale method of blood plasma fractionation was developed by Edwin J. Cohn during

World War II World War II or the Second World War (1 September 1939 – 2 September 1945) was a World war, global conflict between two coalitions: the Allies of World War II, Allies and the Axis powers. World War II by country, Nearly all of the wo ...

. It is known as the Cohn process (or Cohn method). This process is also known as cold ethanol fractionation as it involves gradually increasing the

concentration In chemistry, concentration is the abundance of a constituent divided by the total volume of a mixture. Several types of mathematical description can be distinguished: '' mass concentration'', '' molar concentration'', '' number concentration'', ...

ethanol Ethanol (also called ethyl alcohol, grain alcohol, drinking alcohol, or simply alcohol) is an organic compound with the chemical formula . It is an Alcohol (chemistry), alcohol, with its formula also written as , or EtOH, where Et is the ps ...

in the solution at 5 °C and 3 °C. The Cohn Process exploits differences in properties of the various plasma proteins, specifically, the high

and low pI of albumin. As the ethanol concentration is increased in stages from 0% to 40% the His lowered from neutral (pH ~ 7) to about 4.8, which is near the pI of albumin. At each stage certain proteins are precipitated out of the solution and removed. The final precipitate is purified albumin. Several variations to this process exist, including an adapted method by Nitschmann and Kistler that uses fewer steps and replaces centrifugation and bulk freezing with

filtration Filtration is a physical separation process that separates solid matter and fluid from a mixture using a ''filter medium'' that has a complex structure through which only the fluid can pass. Solid particles that cannot pass through the filte ...

and diafiltration. Some newer methods of albumin purification add additional purification steps to the Cohn Process and its variations, while others incorporate

chromatography In chemical analysis, chromatography is a laboratory technique for the Separation process, separation of a mixture into its components. The mixture is dissolved in a fluid solvent (gas or liquid) called the ''mobile phase'', which carries it ...

, with some methods being purely chromatographic. Chromatographic albumin processing as an alternative to the Cohn Process emerged in the early 1980s, however, it was not widely adopted until later due to the inadequate availability of large scale chromatography equipment. Methods incorporating chromatography generally begin with cryodepleted plasma undergoing buffer exchange via either diafiltration or buffer exchange chromatography, to prepare the plasma for following ion exchange chromatography steps. After ion exchange there are generally further chromatographic purification steps and buffer exchange. ''For further information see chromatography in blood processing.''

Plasma for analytical uses

In addition to the clinical uses of a variety of plasma proteins, plasma has many analytical uses. Plasma contains many biomarkers that can play a role in clinical diagnosis of

diseases A disease is a particular abnormal condition that adversely affects the structure or function of all or part of an organism and is not immediately due to any external injury. Diseases are often known to be medical conditions that are asso ...

, and separation of plasma is a necessary step in the expansion of the human plasma

proteome A proteome is the entire set of proteins that is, or can be, expressed by a genome, cell, tissue, or organism at a certain time. It is the set of expressed proteins in a given type of cell or organism, at a given time, under defined conditions. P ...

Plasma in clinical diagnosis

Plasma contains an abundance of proteins many of which can be used as biomarkers, indicating the presence of certain diseases in an individual. Currently, 2D Electrophoresis is the primary method for discovery and detection of biomarkers in plasma. This involves the separation of plasma proteins on a gel by exploiting differences in their size and pI. Potential disease biomarkers may be present in plasma at very low concentrations, so, plasma samples must undergo preparation procedures for accurate results to be obtained using 2D Electrophoresis. These preparation procedures aim to remove contaminants that may interfere with detection of biomarkers, solubilize the proteins so they are able to undergo 2D Electrophoresis analysis, and prepare plasma with minimal loss of low concentration proteins, but optimal removal of high abundance proteins. The future of laboratory diagnostics are headed toward lab-on-a-chip technology, which will bring the laboratory to the point-of-care. This involves integration of all of the steps in the analytical process, from the initial removal of plasma from whole blood to the final analytical result, on a small microfluidic device. This is advantageous because it reduces turn around time, allows for the control of variables by

automation Automation describes a wide range of technologies that reduce human intervention in processes, mainly by predetermining decision criteria, subprocess relationships, and related actions, as well as embodying those predeterminations in machine ...

, and removes the labor-intensive and sample wasting steps in current diagnostic processes.

Expansion of the human plasma proteome

The human plasma proteome may contain thousands of proteins, however, identifying them presents challenges due to the wide range of concentrations present. Some low abundance proteins may be present in

picogram To help compare different '' orders of magnitude'', the following lists describe various ''mass'' levels between 10−67 kg and 1052 kg. The least massive thing listed here is a graviton, and the most massive thing is the observable univer ...

(pg/mL) quantities, while high abundance proteins can be present in milligram (mg/mL) quantities. Many efforts to expand the human plasma proteome overcome this difficulty by coupling some type of high performance liquid chromatography (HPLC) or reverse phase liquid chromatography (RPLC) with high efficiency cation exchange chromatography and subsequent tandem

mass spectrometry Mass spectrometry (MS) is an analytical technique that is used to measure the mass-to-charge ratio of ions. The results are presented as a ''mass spectrum'', a plot of intensity as a function of the mass-to-charge ratio. Mass spectrometry is used ...

for protein identification.Wu, S., Choudhary, G., et al. 2003. "Evaluation of Shotgun Sequencing for Proteomic Analysis of Human Plasma Using HPLC coupled with Either Ion Trap or Fourier Transform Mass Spectrometry". ''Journal of Proteome Research''. Vol. 2. pp. 383–93.

References

{{DEFAULTSORT:Blood Plasma Fractionation Medical technology Blood Fractionation