Evaluation of innovative polyvinyl alcohol/ alginate/ green palladium nanoparticles composite scaffolds: Effect on differentiated human dental pulp stem cells into osteoblasts.

Three-dimensional (3D) scaffolds are attracting great concern for bone tissue engineering applications. However, selecting an appropriate material with optimal physical, chemical, and mechanical properties is considered a great challenge. The green synthesis approach is essential to avoid the production of harmful by-products through textured construction, sustainable, and eco-friendly procedures. This work aimed at the implementation of natural green synthesized metallic nanoparticles for the development of composite scaffolds for dental applications. In this study, innovative hybrid scaffolds of polyvinyl alcohol/alginate (PVA/Alg) composite loaded with various concentrations of green palladium nanoparticles (Pd NPs) have been synthesized. Various characteristic analysis techniques were used to investigate the synthesized composite scaffold's properties. The SEM analysis revealed impressive microstructure of the synthesized scaffolds dependent on the Pd NPs concentration. The results confirmed the positive effect of Pd NPs doping on the sample stability over time. The synthesized scaffolds were characterized by the oriented lamellar porous structure. The results confirmed the shape stability, without pores breakdown during the drying process. The XRD analysis confirmed that doping with Pd NPs does not affect the crystallinity degree of the PVA/Alg hybrid scaffolds. The mechanical properties results (up to 50 MPa) confirmed the remarkable effect of Pd NPs doping and its concentration on the developed scaffolds. The MTT assay results showed that the incorporation of Pd NPs into the nanocomposite scaffolds is necessary for increasing cell viability. According to the SEM results, the scaffolds with Pd NPs provided the differentiated grown osteoblast cells with enough mechanical support and stability and the cells had a regular form and were highly dense. In conclusion, the synthesized composite scaffolds expressed suitable biodegradable, osteoconductive properties, and the ability to construct 3D structures for bone regeneration, making them a potential option for treating critical deficiencies of bone.

Biocompatibility of hydroxyethyl cellulose/glycine/RuO2 composite scaffolds for neural-like cells.

Fabrication of scaffolds for nerve regeneration is one of the most challenging topics in regenerative medicine at the moment, which is also interlinked with the development of biocompatible substrates for cells growth. This work is targeted towards the development of green biomaterial composite scaffolds for nerve cell culture applications. Hybrid scaffolds of hydroxyethyl cellulose/glycine (HEC/Gly) composite doped with different concentrations of green ruthenium oxide (RuO2) were synthesized and characterized via a combination of different techniques. X-rays diffraction (XRD) and differential scanning calorimetry (DSC) analyses showed a crystalline nature for all the samples with noticeable decrease in the peak intensity of the fabricated scaffolds as compared to that for pure glycine. Fourier transform infrared spectroscopy (FTIR) tests revealed an increase in the vibrational bands of the synthesized RuO2 containing scaffolds which are related to the functional groups of the natural plant extract (Aspalathuslinearis) used for RuO2 nanoparticles (NPs) synthesis. Scanning electron microscopy (SEM) results revealed a 3D porous structure of the scaffolds with variant features attributed to the concentration of RuO2 NPs in the scaffold. The compressive test results recorded an enhancement in mechanical properties of the fabricated scaffolds (up to 8.55 MPa), proportionally correlated to increasing the RuO2 NPs concentration in HEC/Gly composite scaffold. Our biocompatibility tests revealed that the composite scaffolds doped with 1 and 2 ml of RuO2 demonstrated the highest proliferation percentages (152.2 and 135.6%) compared to control. Finally, the SEM analyses confirmed the impressive cells attachments and differentiation onto the scaffold surfaces as evidenced by the presence of many neuron-like cells with apparent cell bodies and possessing few short neurite-like processes. The presence of RuO2 and glycine was due to their extraordinary biocompatibility due to their cytoprotective and regenerative effects. Therefore, we conclude that these scaffolds are promising for accommodation and growth of neural-like cells.

Nanomaterials for Biomedical Applications: Production, Characterisations, Recent Trends and Difficulties.

Designing of nanomaterials has now become a top-priority research goal with a view to developing specific applications in the biomedical fields. In fact, the recent trends in the literature show that there is a lack of in-depth reviews that specifically highlight the current knowledge based on the design and production of nanomaterials. Considerations of size, shape, surface charge and microstructures are important factors in this regard as they affect the performance of nanoparticles (NPs). These parameters are also found to be dependent on their synthesis methods. The characterisation techniques that have been used for the investigation of these nanomaterials are relatively different in their concepts, sample preparation methods and obtained results. Consequently, this review article aims to carry out an in-depth discussion on the recent trends on nanomaterials for biomedical engineering, with a particular emphasis on the choices of the nanomaterials, preparation methods/instruments and characterisations techniques used for designing of nanomaterials. Key applications of these nanomaterials, such as tissue regeneration, medication delivery and wound healing, are also discussed briefly. Covering this knowledge gap will result in a better understanding of the role of nanomaterial design and subsequent larger-scale applications in terms of both its potential and difficulties.

The impact of oral health status on COVID-19 severity, recovery period and C-reactive protein values.

Objectives The oral cavity is a potential reservoir for respiratory pathogens which can predispose patients to bacterial super-infection. Several trials have correlated poor oral hygiene with hyper-inflammation. Similarly, COVID-19 severity has been linked to hyper-inflammatory responses. Hence, in this study, we assumed that increased COVID-19 severity may be linked to poor oral health status. This was achieved through assessing oral health status, severity of COVID-19 symptoms, C-reactive protein (CRP) levels and duration of recovery.Methods Cross-sectional study based on a questionnaire; 308 Egyptian patients with confirmed positive polymerase chain reaction (PCR) tests were included in the study after exclusion criteria. The questionnaire was designed with two sections: the first section for oral health evaluation and the second section for COVID-19 severity evaluation. Assessment of the effect of oral health on COVID-19 severity was performed using an oral health score. The effect of oral health on CRP and recovery period were evaluated as secondary endpoints. Data of CRP levels and COVID-19 PCR tests were collected via the questionnaire and confirmed by reviewing medical records.Results The correlation between oral health and COVID-19 severity showed a significant inverse correlation (p <0.001, r = -0.512). Moreover, the correlation between oral health with recovery period and CRP values also revealed a significant inverse correlation (p <0.001, -0.449 and p <0.001, -0.190, respectively), showing that poor oral health was correlated to increased values of CRP and delayed recovery period.Conclusions Our study provided some evidence that oral health could have a potential impact on the severity of COVID-19. However, the correlation is limited by the study design. A more substantial research project is required to address this relation.

Salivary exosomes as a new therapy to ameliorate diabetes mellitus and combat xerostomia and submandibular salivary glands dysfunction in diabetic rats.

Diabetes mellitus (DM) is one of the major metabolic diseases. Xerostomia and salivary gland dysfunction are of its common oral complications. Exosomes, as a new therapeutic potential containing nucleic acids, proteins and lipids, act as effective vehicles for target molecules delivery. Accordingly, their therapeutic use is gaining much interest. Therefore, this work aimed to assess the therapeutic efficacy of salivary exosomes in ameliorating DM and combating xerostomia as a complication of salivary gland dysfunction in diabetic rats. In the current study, salivary exosomes were injected intravenously to rats of group II (Salivary Exo-treated group) one week after diabetes induction. Group I (Diabetic group) was left untreated. Blood sugar level was checked weekly. Water intake, salivary flow rate, salivary amylase and serum nitric oxide were assessed before and after diabetes induction and at the end of the study. After 5 weeks from the beginning of the study, salivary gland tissues were dissected and examined histologically and ultrastructurally. Gene expression of the inflammatory markers NFκB/p65 and TNFα was assessed by polymerase chain reaction. The results showed that salivary exosomes reduced blood glucose levels and enhanced salivary glands' function. This was indicated by a decrease in water intake, salivary amylase and serum nitric oxide in addition to an increase in salivary flow rate. This was confirmed histologically, ultrastructurally and via downregulation of NFκB/p65 and TNFα gene expression. Our results concluded that salivary exosomes could be considered as a novel cell free based therapy in treatment of xerostomia and salivary gland dysfunction in DM.

Comparative evaluation of the ultrastructural morphology and distribution of filiform and fungiform tongue papillae in Egyptian mice, fruit bats and long-eared hedgehogs.

The tongue is a specialized vital organ. It aids in mastication, deglutition and food digestion. It also shares in the perception of taste sensation as it possesses various gustatory papillae. It is being subjected to numerous anatomical and histological examinations aiming at exploring the correlation between its morphological features and animal adaptations to various types of nutrition and environmental conditions. The goal of the present work was to compare the ultrastructural features of the filiform and fungiform papillae of three various mammals possessing different feeding habits; Egyptian mice, fruit bats and long-eared hedgehogs. Specimens were obtained from the tongues of four healthy adult animals from each mammalian type. Tongues were fixed and all the appropriate procedures were done to perform scanning electron microscopic investigation. Scanning electron microscopic examination demonstrated that in mice, there were four different sub-types of filiform papillae (spike, leaf, conical and tongue-shaped). In bats, there were two sub-types (flower and leaf-like) and in hedgehogs, there was only one type (tongue-like). These filiform papillae showed different distribution and orientation. As for the fungiform papillae, they were cylindrical in mice, rounded or conical in bats and dome-shaped in hedgehogs. Fungiform papillae possessed taste pores containing taste buds. Ultrastructural variations of the filiform and fungiform papillae were suggested to be probably due to adaptation to various feeding habits and different environmental conditions of these animals.

Functional and histological evaluation of bone marrow stem cell-derived exosomes therapy on the submandibular salivary gland of diabetic Albino rats through TGFß/ Smad3 signaling pathway.

BACKGROUND: To prevail over diabetes mellitus and its numerous complications, researchers are seeking new therapies. Exosomes are natural cargo of functional proteins and can be used as a therapeutic delivery of these molecules. OBJECTIVE: The aim of this study was to evaluate the effect of exosomes derived from bone marrow mesenchymal stem cells (BM-MSCs) as a therapeutic intervention in salivary gland diabetic complications. METHODS: Ten adult healthy male Albino rats, weighing about 150-200 g were grouped into 2 groups. Diabetic group I: consisted of 5 streptozotocin (STZ)-induced diabetic rats. Exosomes treated group II: consisted of 5 STZ-induced diabetic rats, each animal received a single injection of exosomes (100 µg/kg/dose suspended in 0.2 ml PBS) through the tail vein. All animals were sacrificed after 5 weeks from the beginning of the experiment. Submandibular salivary gland samples were excised and processed for histological, ultrastructural examination and PCR for TGFß, Smad2 and Smad3. Blood glucose level was monitored weekly, salivary IgA and serum amylase were evaluated before and after diabetes induction and at the end of the experiment. RESULTS: Histological and ultrastructural results of the exosomes treated group were promising regarding the glandular and ductal elements with less fibrosis observed. Results of PCR supported the role of exosomes to inhibit the diabetic sequalae in salivary gland and its complications through inhibiting TGFß and its related pathway via Smad2 and Smad3. Blood glucose levels were reduced. In addition, salivary glands' function was improved as evidenced by reduction in serum amylase and salivary IgA. CONCLUSION: BM-MSC-derived exosomes could be a novel therapeutic strategy for diabetic complications involving salivary glands.

Comparative study of the osteogenic potential of mesenchymal stem cells derived from different sources.

BACKGROUND: Mesenchymal stem cells (MSCs) can regenerate missing tissues and treat diseases. Hence, the current work aimed to compare the proliferation rate and the osteogenic differentiation potential of bone marrow MSCs (BMSCs), gingival MSCs (GMSCs) and submandibular MSCs (SMSCs). MATERIAL AND METHODS: MSCs derived from bone marrow, gingiva and submandibular salivary gland were isolated and cultured from rats. The proliferation capacity was judged by MTT proliferation Assay. Osteogenic differentiation was assessed by Alzarin red stain and quantitative RT-PCR was performed for Runx-2 and MMP-13. RESULTS: The highest significant proliferation was estimated in the BMSCs compared to GMSCs and SMSCs (p-value was < 0.01). All studied cell types formed mineralized nodules as stained with Alizarin Red stain at the 3rd passage of differentiation. However, BMSCs seemed to generate the highest level of mineralization compared to GMSCs and SMSCs. RT-PCR revealed that the expression of Runx-2 and MMP-13 mRNAs was significantly increased in the BMSCs compared to GMSCs and SMSCs (p-value was < 0.01). CONCLUSIONS: BMSCs displayed maximum osteogenesis results followed by the GMSCs and lastly by the SGSCs. Thus, it could be recommended that GMSCs can be used as a second choice after BMSCs when bone tissue reconstruction is needed. Key words:Mesenchymal stem cells, osteogenic differentiation, Runx-2, MMP-13.