Bone marrow stroma

Detailed information about bone marrow stroma

Bone marrow stroma

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Diagram of bone marrow stroma
Latin	stroma medullae ossium
System	Skeletal system

Bone marrow stroma refers to the non-hematopoietic supportive tissue found within the bone marrow. It plays a crucial role in the regulation of hematopoiesis, the process by which blood cells are produced. The stroma provides a microenvironment that supports the growth and differentiation of hematopoietic stem cells (HSCs) into various blood cell lineages.

Structure

The bone marrow stroma is composed of a variety of cell types and extracellular matrix components. Key cellular components include:

• Fibroblasts: These cells produce collagen and other extracellular matrix proteins that provide structural support.
• Adipocytes: Fat cells that store energy and secrete factors influencing hematopoiesis.
• Endothelial cells: These cells line the blood vessels within the marrow and are involved in the formation of the bone marrow niche.
• Osteoblasts: Bone-forming cells that also contribute to the hematopoietic niche.
• Mesenchymal stem cells (MSCs): Multipotent stromal cells that can differentiate into osteoblasts, chondrocytes, and adipocytes.

The extracellular matrix is rich in collagen, fibronectin, and other glycoproteins that provide a scaffold for cell attachment and signaling.

Function

The primary function of the bone marrow stroma is to create a supportive microenvironment for hematopoietic stem cells. This is achieved through:

• Cell-cell interactions: Direct contact between stromal cells and HSCs is crucial for maintaining stem cell quiescence and self-renewal.
• Secretion of cytokines and growth factors: Stromal cells produce a variety of signaling molecules, such as stem cell factor (SCF), interleukins, and colony-stimulating factors, which regulate HSC proliferation and differentiation.
• Regulation of the bone marrow niche: The stroma helps maintain the specialized niches within the bone marrow that are essential for HSC function.

Clinical Significance

Disruptions in the bone marrow stroma can lead to hematological disorders. For example, alterations in stromal cell function or composition can contribute to conditions such as myelodysplastic syndromes and leukemia. Understanding the interactions between stromal cells and hematopoietic cells is crucial for developing therapies for these diseases.

Research and Applications

Research into bone marrow stroma has led to advances in regenerative medicine and stem cell therapy. Mesenchymal stem cells derived from the stroma are being investigated for their potential to repair damaged tissues and treat inflammatory diseases.

Also see

• Hematopoiesis
• Hematopoietic stem cell
• Mesenchymal stem cell
• Bone marrow
• Stem cell niche