Injectable, scalable 3D tissue-engineered model of marrow hematopoiesis

Area of Science:

• Biomaterials Science
• Stem Cell Biology
• Hematopoiesis Research

Background:

• Understanding the bone marrow niche is crucial for blood disorder regeneration.
• Hematopoietic stem and progenitor cells (HSPCs) interact with supportive stromal cells.

Purpose of the Study:

• To develop an injectable co-culture system for studying stromal-HSPC interactions.
• To create a biomimetic in vitro and in vivo model of the hematopoietic niche.

Main Methods:

• Co-culture of OP9 mesenchymal cells and HSPCs in collagen-coated carboxymethylcellulose microscaffolds (CCMs).
• Controlled dehydration to create an injectable living niche biomaterial.
• Subcutaneous injection of the artificial niche into immunodeficient mice.

Main Results:

• The CCM system supported in vitro hematopoiesis without exogenous cytokines.
• Injectable niche maintained cell viability and stromal-HSPC association.
• In vivo, the niche supported stromal and hematopoietic populations for 12 weeks with enhanced vascularization.

Conclusions:

• The developed system is a minimalistic, scalable, and biomimetic model for hematopoiesis.
• The injectable niche preserves HSPC progenitor function and in vitro established cell-cell interactions.
• This approach offers a novel platform for studying bone marrow niche regeneration.