Lanthanum oxide nanoparticle-collagen bio matrix induced endothelial cell activation for sustained angiogenic response for biomaterial integration

Proangiogenic effect and underlying mechanism of holmium oxide nanoparticles: a new biomaterial for tissue engineering

BACKGROUND

Early angiogenesis provides nutrient supply for bone tissue repair, and insufficient angiogenesis will lead tissue engineering failure. Lanthanide metal nanoparticles (LM NPs) are the preferred materials for tissue engineering and can effectively promote angiogenesis. Holmium oxide nanoparticles (HNPs) are LM NPs with the function of bone tissue "tracking" labelling. Preliminary studies have shown that HNPs has potential of promote angiogenesis, but the specific role and mechanism remain unclear. This limits the biological application of HNPs.

RESULTS

In this study, we confirmed that HNPs promoted early vessel formation, especially that of H-type vessels in vivo, thereby accelerating bone tissue repair. Moreover, HNPs promoted angiogenesis by increasing cell migration, which was mediated by filopodia extension in vitro. At the molecular level, HNPs interact with the membrane protein EphrinB2 in human umbilical vein endothelial cells (HUVECs), and phosphorylated EphrinB2 can bind and activate VAV2, which is an activator of the filopodia regulatory protein CDC42. When these three molecules were inhibited separately, angiogenesis was reduced.

CONCLUSION

Overall, our study confirmed that HNPs increased cell migration to promote angiogenesis for the first time, which is beneficial for bone repair. The EphrinB2/VAV2/CDC42 signalling pathway regulates cell migration, which is an important target of angiogenesis. Thus, HNPs are a new candidate biomaterial for tissue engineering, providing new insights into their biological application.

Localized trans-browning and pro-angiogenesis inductive self-assembled collagen resveratrol bio-matrix for tissue repair and regeneration in obese conditions

The present study probes into the complexities of wound management in obesity by proposing a novel biomaterial designed to reprogram the altered skin physiology prevalent in obese conditions. The strategy involves the development of a multifunctional biomaterial addressing issues such as excessive exudate, pressure ulcers, and reduced vascularity. The bio-matrix demonstrates the localized transformation of white adipocytes through trans-browning, coupled with the simultaneous induction of angiogenesis at obese wound sites, resulting in expedited wound closure. The collagen bio-matrices, stabilized with Resveratrol (Rsv), exhibit remarkable thermal, mechanical, and biological stability. The porous 3D microstructure of the Rsv-stabilized collagen bio-matrix closely resembled the natural extracellular matrix, facilitating effective cell adhesion. The bio-matrix exhibited the unique capability to induce localized thermogenesis in the subcutaneous fat layer while concurrently activating angiogenesis. In vivo wound healing studies conducted on DIO-C57BL6 mice demonstrated complete healing within 10 days, showcasing accelerated tissue regeneration, blood vessel formation, robust collagen deposition, and significant activation of browning in the subcutaneous adipose layer. This study introduces the concept of tailored regenerative biomaterials with the ability to reprogram the challenging wound environment associated with obesity. This innovative approach opens up new avenues for enhanced wound care strategies, particularly for bariatric patients.

Apigenin Self-Assembled Collagen Biomatrix for Reprogramming the Obese Wound Microenvironment for Its Management and Repair

Wound management in obesity is complicated by excessive exudates from wounded areas, pressure ulcerations due to stacking of the fat layer, and vascular rarefaction. The current study explored the development of biomaterials for reprogramming the altered wound microenvironment under obese conditions. Self-assembled collagen biomatrix with trans and de novo browning activator, apigenin, was fabricated as a soft tissue regenerative wound dressing material. The as-synthesized self-assembled collagen biomatrix exhibited excellent thermal, mechanical, and biological stability with a superior wound exudate absorption capacity. The apigenin self-assembled collagen biomatrix exhibited porous 3-D microstructure that mimicked the extracellular matrix that promoted cell adhesion and proliferation. The apigenin self-assembled collagen multifunctional biomatrix triggered adaptive localized thermogenesis in the subcutaneous fat layer, resulting in the activation of angiogenesis and fibroblast spreading and migration. The in vivo wound healing assay performed in DIO-C57BL6 mice showed faster tissue regeneration within 9 days, with well-defined neo-epidermis, blood vessel formation, thick collagen deposition, minimal inflammation, and significant activation of browning in the subcutaneous adipose layer. This study paves the way forward for the development of specialized regenerative biomatrices that reprogram the obese wound bed for faster tissue regeneration.

Caffeine-reinforced Collagen as Localized Microenvironmental Trans-Browning Bio-Matrix for Soft Tissue Repair and Regeneration in Bariatric Condition

The wound exudates, hypoperfusion of the subcutaneous fat layer, and poor vasculature worsen wound management in obese subjects. In the current study, a multifunctional Caffeine-reinforced collagen biomaterial is developed that can simultaneously modulate lipid metabolism and angiogenesis in obese wound microenvironments for faster tissue regeneration. The biomaterial is fabricated specialized for obese conditions to initiate simultaneous lipolysis and angiogenesis locally in the hypoxic subcutaneous fat in wound margins of obese subjects. Caffeine-reinforced collagen biomatrix shows better structural integrity, thermal stability, bio-compatibility, and lesser proteolytic susceptibility. Caffeine-collagen biomaterial promote angiogenesis, fibroblast migration, and localized browning of white adipocytes to activate thermogenesis in the subcutaneous fat layer at the wound site. Full-thickness excision wound healing studies performed in obese C57BL6 mice shows faster wound closure within day 9 when compare to control mice. The Caffeine-reinforced collagen biomaterial remodeled the wound site locally by activating fibroblast to secrete collagen, activate endothelial cells to promote angiogenesis, and induce browning in white adipocytes in subcutaneous fat. The study opens a new direction in bariatric tissue regenerative medicine by locally modulating lipid metabolism, angiogenesis, and trans-browning at the injured site for faster complete restoration of the damaged tissue.

Effects of Addition of Lanthanum and Zinc Oxides on the Biological Properties of TiO2-SiO2-P2O5/CaO on Ion Exchange Resin for Bone Implantation

The spherical materials TiO2-SiO2-P2O5/CaO, TiO2-SiO2-P2O5/La2O3, and TiO2-SiO2-P2O5/ZnO deposited on the Tokem-250 cation exchanger have been synthesized with an alcoholic solution by the sol-gel method. The macroporous cation exchanger Tokem-250, which has high Ca2+, Zn2+, and La3+ ion selectivity, was used in the present study. This material has the ability to precipitate and mineralize calcium phosphates on its surface in biological media, since it has high porosity, a homogeneous structure with a uniform variation of elements, and the presence of active centers (Si4+, Ti4+) on the surface. The effect of lanthanum and zinc additives on biological properties has been studied. It was established that accumulation of Ca2+ and Mg2+ occurs faster on the surface of TiO2-SiO2-P2O5/ZnO in the SBF (simulated body fluid) model solution, showing higher reaction capacity. The amount of calcium and phosphorus ions on the surface of sample TiO2-SiO2-P2O5/La2O3 is greater due to the ability of lanthanum to coordinate a large number of ions (lanthanum coordination number is 10). The presence of zinc ions in the system causes the partial hemoglobin release from erythrocytes into the supernatant fluid. The samples with lanthanum ions reduce the amount of protein in plasma after incubation, which has a positive effect on the practical application.

Lanthanum Oxide Nanoparticles Reinforced Collagen ƙ-Carrageenan Hydroxyapatite Biocomposite as Angio-Osteogenic Biomaterial for In Vivo Osseointegration and Bone Repair

A composite biomatrix fabricated with collagen, ƙ-carrageenan, hydroxyapatite reinforced with lanthanum oxide nanoparticles is explored as proangiogenic and osteogenic bone tissue repair biomaterial. The biomatrix shows increased physical and biological stability as observed from proteolytic degradation and thermal stability studies. The addition of lanthanum oxide nanoparticles facilitates good osseointegration coupled with simultaneous activation of proangiogenic properties to act as a bone mimicking material. The minimal level of reactive oxygen species and superior cytocompatibility help the as-synthesized biomatrix in achieving capillary migration into the bone micro environment. The composite biomatrix upregulates the expression of VEGF, VEGF-R2 genes in endothelial cells and osteopontin, osteocalcin in osteoblasts cells, respectively. The in vivo hard tissue repair experiment conducted in a rat model shows complete healing of the bone defect by eight weeks with the application of collagen-ƙ-carrageenan-hydroxyapatite-lanthanum oxide nanoparticle biomaterial when compared to the biomaterial made out of individual constituents alone. The biomaterial matrix gets biointegrated into the bone tissue and exerts its therapeutic value in bringing a faster osseo repair process. The study shows the feasibility of using rare-earth metal nanoparticles in combination with protein-polysaccharide biopolymers for bone regeneration.