Intrafemoral Injection of Human Hematopoietic Stem and Progenitor Cells into Immunocompromised Mice
December 8th, 2023
Intrafemoral injections allow for the engraftment of a small number of hematopoietic stem and progenitor cells (HSPCs), by placing the cells directly in the bone marrow cavity. Here we describe an experimental protocol of intrafemoral injection of human HSPCs into immunodeficient mice.
Our interest is studying healthy human hematopoiesis across a whole lifetime, from the fetus to the elderly. For example, we study the liver in the fetus and the bone marrow and peripheral blood in the adult. We think it is important to study the healthy context to help us understand what goes wrong in disease.
There are many single-cell omics approaches that have advanced the field in recent years, but these work alongside rather than replace transplantation experiments that test the function of stem cells. By injecting blood stem and progenitor cells directly into the femur, we bypass the homing phase of intravenous injections. The cells are already in their natural environment, and therefore we often have much higher engraftment.
We want to provide a quantitative view of how blood stem cells evolve over human life, how they are affected by events such as inflammation or infections, and, finally, how mutations accumulate with age, how they reshape blood stem cell function, and how this predisposes us to age-related disease. To begin, remove the cryovial containing cord blood CD34+cells from the freezer. Thaw the cells in a water bath before transferring them to a 50 milliliter tube.
While shaking the tube, dropwise add 10 times the cells'volume of pre-warmed IMDM containing 50%FBS and 0.1 milligram per milliliter DNAse to the tube. Centrifuge the cell suspension at 500g for five minutes. Re-suspend the pellet in 20 to 40 microliters of PBS containing penicillin and streptomycin.
Store the cells on ice until use. Prepare a 3 milliliter syringe with a 27 gauge half-inch needle. Prepare a 0.5 milliliter insulin syringe with a 29 gauge 12.7 millimeter needle containing cord blood CD 34+cell suspension.
Next, prepare a 1 milliliter insulin syringe with a 29 gauge 0.5 inch needle with 100 microliters of buprenorphine. Transfer the anesthetized mouse to a nose cone, and perform a toe pinch to confirm its readiness for the injection. Lay the mouse on its back, and flex its hind legs.
To secure the hind legs, place the thumb of the nondominant hand on the foot, the middle finger on the hip, and the index finger on the outside of the femur. Gently pluck the hair from around the kneecap, and wipe the area with an alcohol swab. Now, using a 3 milliliter syringe with a 27 gauge half-inch needle, gently drill a hole through the skin towards the femur.
Once the needle is in the bone, rotate it clockwise until the whole needle is in the bone. Remove the needle using an anti-clockwise rotation until halfway out. Wipe around the needle with an alcohol swab, and continue to turn the needle anti-clockwise for a complete removal.
Next, insert the 0.5 milliliter insulin syringe containing cell suspension into the femoral shaft. Once the needle is in the bone, release the grip on the leg, and gently inject 25 microliters of suspension into the femur. Finally, inject the buprenorphine subcutaneously, and return the mouse to its home cage, allowing it to recover from anesthesia.
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Overview
This study investigates the dynamics of hematopoietic stem and progenitor cells (HSPCs) across human development, utilizing intrafemoral injection in immunodeficient mice to enhance cell engraftment. By placing HSPCs directly into the bone marrow, the research aims to improve our understanding of normal blood cell development and the influence of age and disease.
Key Study Components
Research Area
- Stem cell biology
- Human hematopoiesis
- Disease modeling
Background
- Healthy human hematopoiesis is studied from fetal stages to elderly.
- Understanding the healthy context aids in deciphering disease mechanisms.
- Transplantation experiments provide functional insights into stem cell behavior.
Methods Used
- Intrafemoral injection of human HSPCs
- Immunodeficient mouse model
- Cell culturing and preparation techniques
Main Results
- Direct injection leads to higher stem cell engraftment.
- Provides a quantitative perspective on aging and stem cell function.
- Highlights the impact of external factors like inflammation on stem cells.
Conclusions
- The study demonstrates effective methods for HSPC engraftment.
- Offers insights into blood stem cell evolution and disease predisposition.
Frequently Asked Questions
Executive Industry Relevance
Direct intrafemoral injection of human hematopoietic stem and progenitor cells (HSPCs) into immunocompromised mice enables precise functional validation of stem cell populations in a disease-relevant in vivo context. This approach enhances engraftment efficiency, supporting robust quantitative assessment of human hematopoiesis across developmental and aging stages. The method strengthens predictive confidence in early discovery and translational research pipelines by reducing biological variability and improving statistical power.
Strategic Applications in Biopharma R&D
Early Discovery & Target Validation
- Enables rigorous functional interrogation of human HSPC populations in vivo.
- Supports mechanistic de-risking by bypassing homing variability seen in intravenous models.
- Facilitates quantitative assessment of stem cell evolution and response to biological stressors.
- Improves predictive confidence for target validation in hematopoietic research.
Screening & Assay Development
- Provides a validated in vivo system for evaluating stem cell engraftment and lineage output.
- Enhances assay reproducibility by standardizing cell delivery directly to the bone marrow niche.
- Enables quantitative flow cytometry-based measurement of multilineage graft composition.
- Supports scalable xenotransplantation workflows for compound or genetic screening.
Translational & Preclinical Research
- Aligns with disease-relevant modeling of human hematopoiesis and age-related dysfunction.
- Enables continuity from discovery-stage findings to preclinical validation of therapeutic hypotheses.
- Supports risk-adjusted advancement decisions by providing robust in vivo functional data.
- Facilitates translational biomarker development through quantitative engraftment metrics.
Pipeline & Workflow Integration
This intrafemoral injection protocol positions itself at the intersection of early discovery, target validation, and preclinical modeling within the hematopoietic research continuum.
- Discovery Biology: Supports hypothesis testing on stem cell function, aging, and disease predisposition in a controlled in vivo setting.
- Screening: Delivers reproducible, quantitative engraftment data suitable for downstream compound or genetic screens.
- Analytics: Enables flow cytometry-based measurement of multilineage reconstitution and graft size for comparative analysis.
- Translational Research: Provides a platform for modeling human hematopoiesis and evaluating translational biomarkers of stem cell health.
- Enterprise Reuse: Offers a standardized, scalable protocol adaptable to diverse experimental designs and donor cell sources.
Operational & Enterprise Impact
- Scientific Value: Increases predictive confidence and reduces mechanistic ambiguity in stem cell research.
- Operational Value: Improves standardization, reproducibility, and scalability of in vivo engraftment assays.
- Strategic Value: Enables more informed go/no-go decisions and enhances capital efficiency by reducing animal usage.
- Portfolio Impact: Supports risk-adjusted prioritization and advancement of hematopoietic targets and therapeutic strategies.
Implementation Considerations
- Requires expertise in small animal surgery and in vivo transplantation techniques.
- Demands access to immunocompromised mouse models and flow cytometry infrastructure.
- Necessitates cross-team standardization of cell preparation and injection protocols.
- Adaptable to both human and mouse donor cells for diverse experimental needs.
- Potential limitations include technical variability and the need for precise surgical skills.
