Bone regeneration

• Affinity Modifications of Porous Microscaffolds Impact Bone Regeneration by Modulating the Delivery Kinetics of Small Extracellular Vesicles
• Nano-zinc oxide (nZnO) targets the AMPK-ULK1 pathway to promote bone regeneration
• A unique presentation of an osteolytic chronic lymphocytic leukemia/small lymphocytic lymphoma as a helmet-shaped tumor
• Spontaneous bone regeneration after decompressive craniectomy performed for an infant with acute subdural hematoma
• The mechanisms and applications of endothelial progenitor cell therapy in the treatment of intracranial aneurysm
• High frequency exercise after human cranial bone-derived mesenchymal stem cells transplantation enhances motor functional recovery following traumatic brain injury in mice
• Olfactory mucosa-mesenchymal stem cells with overexpressed Nrf2 modulate angiogenesis and exert anti-inflammation effect in an in vitro traumatic brain injury model
• Clinical efficacy and safety of P-15 peptide enhanced bone graft substitute in surgical bone regenerative procedures in adult maxillofacial, spine, and trauma patients : a systematic literature review

Bone regeneration refers to the natural or assisted process by which new bone is formed to repair or replace damaged or lost bone tissue.

It is a biological process involving the coordination of:

Cells:

Osteoblasts (form new bone)

Osteoclasts (remove old bone)

Mesenchymal stem cells (can become bone cells)

Signals:

Growth factors like BMPs (Bone Morphogenetic Proteins), VEGF (Vascular Endothelial Growth Factor)

Matrix:

Extracellular scaffold where cells attach and grow.

💥 When does it happen? After a fracture

After surgical bone removal (e.g. tumors, cysts)

In periodontal disease

In bone grafting or implant placement

During regenerative therapies using biomaterials or stem cells

🧰 Types of bone regeneration strategies: Strategy Description Autograft Bone taken from the same person (e.g., hip) – gold standard. Allograft Bone from a donor (cadaver) – no need for second surgery. Xenograft Bone from another species (e.g., bovine). Synthetic materials Ceramics (HA, β-TCP), polymers (like PLGA), or composites. Tissue engineering Scaffolds + cells + growth factors (e.g., stem cells on PLGA scaffolds). Biological stimulation Use of growth factors (e.g., BMP-2, PRP) to stimulate natural healing.

⏳ Phases of bone regeneration: Inflammation (first few days) – Blood clot forms, immune cells come in.

Soft callus formation (1–2 weeks) – Fibrocartilage and early bone matrix appear.

Hard callus formation (2–6 weeks) – Mineralization occurs, forming woven bone.

Remodeling (months) – Woven bone turns into strong, lamellar bone.

🚀 Latest advances: 3D-printed scaffolds

Smart biomaterials with controlled drug delivery

Stem cell therapies

Gene therapy

sEV-based therapies (as in the study you mentioned)

The rabbit cranial defect model is a type of animal model used in preclinical research to study bone regeneration and healing. In this model, a defect is created in the rabbit's skull and various treatments or interventions are tested to assess their effectiveness in promoting bone regeneration and healing. The rabbit is a commonly used animal model due to its relatively large size and similarity to humans in terms of bone physiology and healing mechanisms.