What are the different types of collagen and their properties?

From the Guidelines

Collagen is the most abundant protein in the human body, with at least 28 different types identified, and the five most common types are Type I, II, III, IV, and V, each with distinct properties and functions. The different types of collagen have various properties, including:

• Type I collagen, which is the most abundant, making up about 90% of the body's collagen and providing structure to skin, bones, tendons, and fibrous cartilage, forming strong, thick fibers that give tensile strength to tissues 1
• Type II collagen, which is primarily found in cartilage, forming thinner fibers that provide cushioning for joints, and has a high density in septal and lobular cartilage, particularly in the peripheral zones 1
• Type III collagen, which supports the structure of muscles, organs, and blood vessels, often working alongside Type I to provide structural support and elasticity, and has been proposed as the ligand of GPR56, signaling by activating RhoA through coupling to G12/13 1
• Type IV collagen, which differs by forming a mesh-like structure rather than fibers and is essential for basement membranes, acting as a filtration system in various tissues including the kidneys
• Type V collagen, which is found in cell surfaces, hair, and placental tissue, helping to regulate fiber formation of other collagen types. Each type has specific amino acid compositions and molecular structures that determine its physical properties, such as tensile strength, flexibility, and resistance to stretching, allowing collagen to perform diverse functions throughout the body, from providing rigid structure in bones to offering flexibility in skin and blood vessels.

The properties of collagen types are crucial in understanding their roles in various tissues and organs, and their involvement in different diseases and conditions, such as Osteogenesis Imperfecta, which is a collagen type I disorder, characterized by fragile bones and other systemic manifestations 1.

In terms of their distribution and function, collagen types have distinct characteristics, such as:

• Type I collagen, which is widely distributed in skin, bones, tendons, and fibrous cartilage, providing structural support and tensile strength
• Type II collagen, which is primarily found in cartilage, providing cushioning and support for joints
• Type III collagen, which is found in muscles, organs, and blood vessels, providing structural support and elasticity
• Type IV collagen, which is essential for basement membranes, acting as a filtration system in various tissues
• Type V collagen, which is found in cell surfaces, hair, and placental tissue, regulating fiber formation of other collagen types.

Overall, the different types of collagen have unique properties and functions, and their understanding is essential in the diagnosis and treatment of various diseases and conditions.

From the Research

Types of Collagen

• There are 28 types of collagens encoded by 43 genes in humans, which fall into several different functional protein classes 2
• The main types of collagen mentioned in the studies include:
  • Type I collagen: the most prevalent collagen type, essential for the structural integrity of various tissues, and the main constituent of the interstitial matrix 3
  • Type II collagen: associated with chondrodysplasias, a group of disorders that affect cartilage and bone development 2
  • Type III collagen: associated with vascular Ehlers-Danlos syndrome, a disorder that affects the blood vessels and other tissues 2

Properties of Collagen

• Collagen type I has high biocompatibility in human tissue and makes up the larger protein component (90%) in vasculature, skin, tendon bone, and other tissue 4
• Type I collagen is unique due to its acceptable physicochemical properties, which enhance its incorporation in various fields, including pharmaceutical, cosmeceutical, regenerative medicine, and clinical 4
• Mutations in the type I collagen genes (COL1A1 and COL1A2) can cause osteogenesis imperfecta (OI) and Ehlers-Danlos syndrome (EDS) 5, 6
• The molecular structure, synthesis, assembly, and breakdown of collagen are vital for comprehending embryonic and foetal development and several aspects of human physiology 3

Collagen-Related Disorders

• Osteogenesis imperfecta (OI): a disorder characterized by fragile bones that are susceptible to fractures, caused by mutations in the type I collagen genes (COL1A1 and COL1A2) 3, 5, 6
• Ehlers-Danlos syndrome (EDS): a disorder that affects the blood vessels and other tissues, caused by mutations in the type III collagen gene (COL3A1) or other collagen genes 5, 2, 6
• Chondrodysplasias: a group of disorders that affect cartilage and bone development, associated with mutations in the type II collagen gene (COL2A1) 2