Engineered Microalgae Promoting Angiogenesis for Diabetic Bone Regeneration

Area of Science:

• Biomaterials Science
• Regenerative Medicine
• Nanotechnology

Background:

• Diabetic bone defects involve hyperglycemia, advanced glycation end products (AGEs), oxidative stress, and inflammation, impairing bone regeneration and angiogenesis.
• Current treatments for diabetic bone defects are limited due to the complex pathological microenvironment.

Purpose of the Study:

• To investigate the therapeutic potential of palladium (Pd)-engineered Spirulina platensis (SPP) for diabetic bone regeneration.
• To evaluate SPP's ability to modulate the diabetic bone microenvironment and promote angiogenesis.

Main Methods:

• Engineered SPP by incorporating palladium nanoparticles into Spirulina platensis.
• Assessed SPP's effects on endothelial cells under hyperglycemic conditions, including reactive oxygen species (ROS) and AGEs reduction, macrophage polarization, and human umbilical vein endothelial cell (HUVEC) function.
• Incorporated SPP into a 3D-bioprinted hydrogel scaffold (SPP@Gel).
• Evaluated SPP@Gel in a critical-sized cranial defect model in diabetic rats.

Main Results:

• SPP significantly reduced intracellular ROS and AGEs accumulation in endothelial cells compared to native Spirulina platensis.
• SPP promoted M1 to M2 macrophage polarization and enhanced HUVEC proliferation, migration, and tube formation under hyperglycemia.
• SPP treatment upregulated the HIF-1α/VEGF signaling axis.
• SPP@Gel accelerated cranial defect repair in diabetic rats by reducing AGEs and inflammation and promoting local angiogenesis.

Conclusions:

• Pd nanoparticle engineering potentiates the bioactivity of Spirulina platensis for therapeutic applications.
• SPP@Gel demonstrates significant potential for promoting diabetic bone regeneration by modulating the microenvironment and enhancing angiogenesis.
• This study presents a novel strategy for addressing diabetic bone defects using engineered microalgae-based biomaterials.