Polyhedral Oligomeric Silsesquioxane /Platelets Rich Plasma/Gelrite-Based Hydrogel Scaffold for Bone Tissue Engineering

Mesoporous silica and alumina nanoparticles to improve drug delivery of pioglitazone on diabetic type 1 nephropathy in rats

Background and purpose

Diabetic nephropathy leads to end-stage renal disease. The present study aimed to evaluate the prophylactic effect of pioglitazone-loaded mesoporous silica and alumina scaffold on renal function and the underlying mechanisms in streptozotocin-induced diabetic rats.

Experimental approach

The mesoporous nanoparticles were synthesized by chemical methods from tetraethylorthosilicate and aluminum isopropoxide and characterized by Fourier transform infrared spectroscopy, X-ray diffraction, and scanning electron microscopy. The soaking method was applied to load pioglitazone into the mesoporous silica and alumina. Subsequently, the most capable formulation was evaluated for lipid profile, blood glucose, renal function biomarkers, malondialdehyde, and kidney histopathological changes in diabetic rats.

Findings/Results

Pioglitazone loaded in the mesoporous included a superior release of about 80%. No interaction was observed in Fourier transform infrared spectroscopy and X-ray diffraction was shown crystalline. Scanning electron microscopy showed the size of the nanometer in the range of 100 - 300 nm. Mesoporous silica containing the drug significantly decreased urinary parameters, triglycerides, low-density lipoprotein, blood urea nitrogen, blood glucose, malondialdehyde, and creatinine. In addition, it showed increased high-density lipoprotein, significantly. The renal histopathological changes indicated improvement compared with the untreated diabetic group.

Conclusion and implications

It was concluded that the mesoporous was potent to serve as a promising drug carrier and a platform aimed at the delivery of poorly water-soluble drugs for improving oral bioavailability. Furthermore, it has the potential to provide a beneficial effect on the changes in diabetic parameters.

A multifunctional composite hydrogel that sequentially modulates the process of bone healing and guides the repair of bone defects

Calcium carbonate (CaCO3), which exhibits excellent biocompatibility and bioactivity, is a well-established bone filling material for bone defects. Here, we synthesized CaCO3microspheres (CMs) to use as an intelligent carrier to load bone morphogenetic protein-2 (BMP-2). Subsequently, drug-loaded CMs and catalase (CAT) were added to methacrylated gelatin (GelMA) hydrogels to prepare a composite hydrogel for differential release of the drugs. CAT inside hydrogels was released with a fast rate to eliminate H2O2and generate oxygen. Constant BMP-2 release from CMs induced rapid osteogenesis. Resultsin vitroindicated that the composite hydrogels efficiently reduced the level of intracellular reactive oxygen species, preventing cells from being injured by oxidative stress, promoting cell survival and proliferation, and enhancing osteogenesis. Furthermore, animal experiments demonstrated that the composite hydrogels were able to inhibit the inflammatory response, regulate macrophage polarization, and facilitate the healing of bone defects. These findings indicate that a multi-pronged strategy is greatly expected to promote the bone healing by modulating pathological microenvironments.

3D printed polylactic acid/gelatin-nano-hydroxyapatite/platelet-rich plasma scaffold for critical-sized skull defect regeneration

BACKGROUND

Three-dimensional (3D) printing is a capable approach for the fabrication of bone tissue scaffolds. Nevertheless, a purely made scaffold such as polylactic acid (PLA) may suffer from shortcomings and be restricted due to its biological behavior. Gelatin, hydroxyapatite and platelet-rich plasma (PRP) have been revealed to be of potential to enhance the osteogenic effect. In this study, it was tried to improve the properties of 3D-printed PLA scaffolds by infilling them with gelatin-nano-hydroxyapatite (PLA/G-nHA) and subsequent coating with PRP. For comparison, bare PLA and PLA/G-nHA scaffolds were also fabricated. The printing accuracy, the scaffold structural characterizations, mechanical properties, degradability behavior, cell adhesion, mineralization, systemic effect of the scaffolds on the liver enzymes, osteocalcin level in blood serum and in vivo bone regeneration capability in rat critical-sized calvaria defect were evaluated.

RESULTS

High printing accuracy (printing error of < 11%) was obtained for all measured parameters including strut thickness, pore width, scaffold density and porosity%. The highest mean ultimate compression strength (UCS) was associated with PLA/G-nHA/PRP scaffolds, which was 10.95 MPa. A slow degradation rate was observed for all scaffolds. The PLA/G-nHA/PRP had slightly higher degradation rate, possibly due to PRP release, with burst release occurred at week 4. The MTT results showed that PLA/G-nHA/PRP provided the highest cell proliferation at all time points, and the serum biochemistry (ALT and AST level) results indicated no abnormal/toxic influence caused by scaffold biomaterials. Superior cell adhesion and mineralization were obtained for PLA/G-nHA/PRP. Furthermore, all the developed scaffolds showed bone repair capability. The PLA/G-nHA/PRP scaffolds could better support bone regeneration than bare PLA and PLA/G-nHA scaffolds.

CONCLUSION

The PLA/G-nHA/PRP scaffolds can be considered as potential for hard tissue repair.

In vivo assessment of bone repair by an injectable nanocomposite scaffold for local co-delivery of autologous platelet-rich plasma and calcitonin in rat model

Background: Gellan gum is obtained from the bacterium Sphingomonas elodea and is a polysaccharide with carboxylic acid functional groups. The goal of this project was to investigate the osteoinductive effect of local administration of calcitonin through an injectable scaffold of gellan gum containing salmon calcitonin loaded in silsesquioxane nanoparticles, hydroxyapatite, and platelets rich plasma.Methods: The femur of rats was defected by creating a 2 × 5 mm² hole using an electric drill. The defect was filled with an injectable hydrogel scaffold composed of gellan gum enriched with salmon calcitonin loaded in silsesquioxane nanoparticles, hydroxyapatite, platelets rich plasma and then the radiologic images were taken. Bone densitometry and the histologic studies were carried out by Hematoxylin & Eosin test. Biochemical analysis was done to measure the serum alkaline phosphatase (ALP), calcium, calcitonin concentration.Results: Healing of the bone defects and bone densitometry in the treated group by calcitonin-loaded scaffold was significantly higher (p < 0.05) and bone formation occupied 75% of the defect that was greater than other groups. Serum ALP and calcium levels in the scaffold-loaded calcitonin group were more than the other groups (p < 0.05). The osteogenic marker genes also increased significantly (p < 0.05) with free calcitonin and the scaffold.Conclusions: Gellan gum-based scaffold loaded with calcitonin may be considered a promising local treatment to progress bone formation in repairing of skeletal injuries.

The Opportunities and Challenges regarding Induced Platelets from Human Pluripotent Stem Cells

As a standard clinical treatment, platelet transfusion has been employed to prevent hemorrhage in patients with thrombocytopenia or platelet dysfunctions. Platelets also show therapeutic potential for aiding liver regeneration and bone healing and regeneration and for treating dermatological conditions. However, the supply of platelets rarely meets the rising clinical demand. Other issues, including short shelf life, strict storage temperature, and allogeneic immunity caused by frequent platelet transfusions, have become serious challenges that require the development of high-yielding alternative sources of platelets. Human pluripotent stem cells (hPSCs) are an unlimited substitution source for regenerative medicine, and patient-derived iPSCs can provide novel research models to explore the pathogenesis of some diseases. Many studies have focused on establishing and modifying protocols for generating functional induced platelets (iPlatelets) from hPSCs. To reach high efficiency production and eliminate the exogenous antigens, media supplements and matrix have been optimized. In addition, the introduction of some critical transgenes, such as c-MYC, BMI1, and BCL-XL, can also significantly increase hPSC-derived platelet production; however, this may pose some safety concerns. Furthermore, many novel culture systems have been developed to scale up the production of iPlatelets, including 2D flow systems, 3D rotary systems, and vertical reciprocal motion liquid culture bioreactors. The development of new gene-editing techniques, such as CRISPR/Cas9, can be used to solve allogeneic immunity of platelet transfusions by knocking out the expression of B2M. Additionally, the functions of iPlatelets were also evaluated from multiple aspects, including but not limited to morphology, structure, cytoskeletal organization, granule content, DNA content, and gene expression. Although the production and functions of iPlatelets are close to meeting clinical application requirements in both quantity and quality, there is still a long way to go for their large-scale production and clinical application. Here, we summarize the diverse methods of platelet production and update the progresses of iPlatelets. Furthermore, we highlight recent advances in our understanding of key transcription factors or molecules that determine the platelet differentiation direction.

Calcitonin-loaded octamaleimic acid-silsesquioxane nanoparticles in hydrogel scaffold support osteoinductivity in bone regeneration

Novel osteoinductive scaffolds fabricated using the benefits of tissue engineering techniques accompanied by utilizing drugs can accelerate bone regeneration. The purpose of this study was to load salmon calcitonin (sCT) in octamaleimic acid-silsesquioxane (OMA-POSS) nanoparticles and enrich the hydrogel scaffold based on hydroxyapatite, Gelrite® and platelet-rich plasma (PRP) for use in bone tissue engineering. The loading efficiency, release percentage, particle size and zeta potential of the nanoparticles were evaluated. The proliferation of seeded MG-63 osteoblast cells on the designed scaffold, its cytotoxicity and osteo-conductivity were studied by alkaline phosphatase measurement and Alizarin red staining. The expression of cellular osteogenic markers such as collagen 1 (COL1A1), osteocalcin (BGLAP) and osteopontin (SPP1) was examined using reverse transcription polymerase chain reaction. The results revealed that the particle size of the nanoparticles varied between 94.2 and 199.2 nm and their negative surface charge increased after drug conjugation. The osteoblast cell proliferation and calcium granule production in the optimum formulation were significantly higher in comparison with the control group (p < 0.05). Osteogenic markers increased significantly after a specific number of days of cell culture compared to the control group (p < 0.05). The results also showed the potential of the designed scaffold in bone tissue engineering.