Haemoglobin in Chondrocytes | 04 Nov 2023

Source: TH

Why in News?

A recent serendipitous discovery in a study published in Nature found that chondrocytes, which produce cartilage, also produce and rely on haemoglobin for their survival, revealing that haemoglobin isn't exclusive to red blood cells (RBCs).

• Chondrocytes are the cells that make cartilage, the connecting tissue between bones.

What are Haemoglobin Bodies or ‘Hedy’?

• Discovery:
  • In 2017, a pathologist in China, came across spherical structures (while studying growth plates, which are cartilaginous tissue at the end of certain long bones) that bore a striking resemblance to RBCs and contained haemoglobin.
    • The discovery of functional haemoglobin in cartilage also leads to the possibility that it plays a role in certain joint diseases as there are many bone deformities that develop from defects in chondrocytes.
• Formation of Haemoglobin Bodies:
  • The structures, referred to as 'haemoglobin bodies' or 'Hedy,' were found within chondrocytes in the cartilage, and they appeared to form via a process similar to phase separation, akin to oil separating from water.
• Insights into Stem Cells:
  • Research found a special group of stem cells in the growth plate in 2018, and is excited about the potential implications of this discovery for stem cells in the growth plate.
    • One exciting idea is that the haemoglobin in the growth plate might influence the destiny of these stem cells.

What is the Significance of Haemoglobin in Chondrocytes?

• Haemoglobin's Importance in Chondrocytes:
  • Haemoglobin is essential for the survival of chondrocytes, the cells that form cartilage. Without haemoglobin, chondrocytes die and cause embryonic lethality in mice (as experiments were conducted on mice).
• Haemoglobin's Role in Oxygen Transport and Storage in Chondrocytes:
  • Haemoglobin helps chondrocytes cope with low oxygen levels by transporting oxygen within the cells. Without haemoglobin, chondrocytes suffer from hypoxic stress and impaired function.
  • Haemoglobin acts as an oxygen reservoir for chondrocytes, releasing oxygen when needed. Without haemoglobin, chondrocytes cannot maintain adequate oxygen levels and die.