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Chondroblasts

What Are They, Function, and More

Author: Jessica Rivas

Editors: Lisa Miklush PhD, RN, CNS, Ahaana Singh

Illustrator: Jillian Dunbar

What are chondroblasts?

Chondroblasts (AKA perichondrial cells) are cells that play an important role in the formation of cartilage (AKA chondrogenesis). They are located in the perichondrium, which is a layer of connective tissue that surrounds developing bone and also helps protect cartilage. Cartilage is the main type of connective tissue in the body and serves many functions.

What do chondroblasts do?

Chondroblasts contribute to the formation of the extracellular matrix and are the precursors of the chondrocytes, which collectively make up cartilage. Chondroblasts secrete the extracellular matrix which is composed of various substances, including collagen, proteoglycans, glycoproteins, hyaluronic acid, water, and macromolecules. These substances provide strength and structural support to the developing cartilage. In addition, chondroblasts mature into chondrocytes, which make up the cellular components of cartilage. These cells also contribute to the appositional growth of cartilage, which is characterized by the thickening of existing cartilage. They do this by secreting the extracellular matrix at the peripheral cartilage surfaces. 

In existing cartilage, chondrocytes can be damaged or destroyed. When this happens the remaining chondrocytes differentiate into chondroblasts in order to secrete more extracellular matrix and regenerate the lost cartilage tissue. However, this cartilage regeneration process is very slow, in part because of the lack of adequate blood supply. 

In some cases, unregulated chondroblast growth and function can lead to the formation of chondroblastomas or chondrosarcomas. Chondroblastomas are benign tumors that form at endochondral ossification sites (places where growing cartilage is replaced by bone). They most commonly occur on the thigh bone (femur), shinbone (tibia), or humerus, located in the upper arm. On the other hand, chondrosarcomas are malignant tumors originating from the chondroblasts, and make up about 30% of bone cancer cases.

What are the most important facts to know about chondroblasts?

Chondroblasts, located in the perichondrium, are cells that play an important role in the development of cartilage. By producing extracellular matrix, chondroblasts create the main component that provides structure and strength to cartilage. These cells also mature into chondrocytes which make up the cellular component of cartilage. Condroblasts also support appositional growth, or the thickening of cartilage, by adding extracellular matrix to peripheral cartilage. Additionally, when cartilage tissue is damaged, chondrocytes differentiate into chondroblasts to regenerate cartilage. Unregulated growth and stimulation of chondroblasts can result in chondroblastomas (benign tumor) or a chondrosarcoma (malignant tumor).

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