Rouleaux
Encyclopedia
Rouleaux are stacks of red blood cells (RBCs) which form because of the unique discoid shape of the cells in vertebrate
body. The flat surface of the discoid RBCs give them a large surface area to make contact and stick to each other; thus, forming a rouleau. They occur when the plasma protein
concentration is high, and because of them the ESR (erythrocyte sedimentation rate
) is also increased. This is a non-specific indicator of the presence of disease.
Conditions which cause rouleaux formation include infections, Multiple myeloma
, inflammatory
and connective tissue disorders, and cancers. It also occurs in diabetes mellitus
and is one of the causative factors for microvascular occlusion in diabetic retinopathy
.
The presence of acute phase proteins, particularly fibrinogen
, interacts with sialic acid
on the surface of RBC and allows the formation of rouleau. Anaemia, by altering the ratio of RBC to plasma
, increases rouleaux formation and accelerates sedimentation.
Rouleaux formation is retarded by albumin proteins.
Rouleaux formations are also adopted by spermatozoa as a means of cooperation between genetically similar gametocytes so as to improve reproductive success through enhanced motility and, therefore, fertilization capacity, e.g. in the guinea pig
.
of aggregation of colloids is based on the assumption that each particle is surrounded by a "sphere influence”. Single spherical particles, which undergo Brownian motion
collide and sticking of particles happens. As aggregation proceeds, the average diffusion constant of the aggregate population decreases. The aggregation of red blood cells progresses in the same manner except that cells are biconcave rather than spherical.
Vertebrate
Vertebrates are animals that are members of the subphylum Vertebrata . Vertebrates are the largest group of chordates, with currently about 58,000 species described. Vertebrates include the jawless fishes, bony fishes, sharks and rays, amphibians, reptiles, mammals, and birds...
body. The flat surface of the discoid RBCs give them a large surface area to make contact and stick to each other; thus, forming a rouleau. They occur when the plasma protein
Protein
Proteins are biochemical compounds consisting of one or more polypeptides typically folded into a globular or fibrous form, facilitating a biological function. A polypeptide is a single linear polymer chain of amino acids bonded together by peptide bonds between the carboxyl and amino groups of...
concentration is high, and because of them the ESR (erythrocyte sedimentation rate
Erythrocyte sedimentation rate
The erythrocyte sedimentation rate , also called a sedimentation rate or Biernacki Reaction, is the rate at which red blood cells sediment in a period of 1 hour...
) is also increased. This is a non-specific indicator of the presence of disease.
Conditions which cause rouleaux formation include infections, Multiple myeloma
Multiple myeloma
Multiple myeloma , also known as plasma cell myeloma or Kahler's disease , is a cancer of plasma cells, a type of white blood cell normally responsible for the production of antibodies...
, inflammatory
Inflammation
Inflammation is part of the complex biological response of vascular tissues to harmful stimuli, such as pathogens, damaged cells, or irritants. Inflammation is a protective attempt by the organism to remove the injurious stimuli and to initiate the healing process...
and connective tissue disorders, and cancers. It also occurs in diabetes mellitus
Diabetes mellitus
Diabetes mellitus, often simply referred to as diabetes, is a group of metabolic diseases in which a person has high blood sugar, either because the body does not produce enough insulin, or because cells do not respond to the insulin that is produced...
and is one of the causative factors for microvascular occlusion in diabetic retinopathy
Diabetic retinopathy
Diabetic retinopathy is retinopathy caused by complications of diabetes mellitus, which can eventually lead to blindness....
.
The presence of acute phase proteins, particularly fibrinogen
Fibrinogen
Fibrinogen is a soluble plasma glycoprotein, synthesised by the liver, that is converted by thrombin into fibrin during blood coagulation. This is achieved through processes in the coagulation cascade that activate the zymogen prothrombin to the serine protease thrombin, which is responsible for...
, interacts with sialic acid
Sialic acid
Sialic acid is a generic term for the N- or O-substituted derivatives of neuraminic acid, a monosaccharide with a nine-carbon backbone. It is also the name for the most common member of this group, N-acetylneuraminic acid...
on the surface of RBC and allows the formation of rouleau. Anaemia, by altering the ratio of RBC to plasma
Blood plasma
Blood plasma is the straw-colored liquid component of blood in which the blood cells in whole blood are normally suspended. It makes up about 55% of the total blood volume. It is the intravascular fluid part of extracellular fluid...
, increases rouleaux formation and accelerates sedimentation.
Rouleaux formation is retarded by albumin proteins.
Rouleaux formations are also adopted by spermatozoa as a means of cooperation between genetically similar gametocytes so as to improve reproductive success through enhanced motility and, therefore, fertilization capacity, e.g. in the guinea pig
Guinea pig
The guinea pig , also called the cavy, is a species of rodent belonging to the family Caviidae and the genus Cavia. Despite their common name, these animals are not in the pig family, nor are they from Guinea...
.
Kinetics of Linear Rouleaux Formation
According to Smoluchowski, the kineticsChemical kinetics
Chemical kinetics, also known as reaction kinetics, is the study of rates of chemical processes. Chemical kinetics includes investigations of how different experimental conditions can influence the speed of a chemical reaction and yield information about the reaction's mechanism and transition...
of aggregation of colloids is based on the assumption that each particle is surrounded by a "sphere influence”. Single spherical particles, which undergo Brownian motion
Brownian motion
Brownian motion or pedesis is the presumably random drifting of particles suspended in a fluid or the mathematical model used to describe such random movements, which is often called a particle theory.The mathematical model of Brownian motion has several real-world applications...
collide and sticking of particles happens. As aggregation proceeds, the average diffusion constant of the aggregate population decreases. The aggregation of red blood cells progresses in the same manner except that cells are biconcave rather than spherical.
External links
- Rouleaux: Presented by the University of Virginia