Biocompatibility improvement of artificial cornea using chitosan-dextran nanoparticles containing bioactive macromolecules obtained from human amniotic membrane.

Corneal transplantation, by which the damaged cornea is replaced by a new one, suffers from limited access to HLA-compatible-donors and high maintenance and surgical costs. Therefore, artificial corneas are considered as alternative tools with promising prospects. In our previous study, a two-part-polymeric artificial cornea was composed of enhanced hydrophilic surface electrospun poly(ε-caprolactone) nanofibrous scaffold that is thermally connected to a polyvinyl alcohol-based hydrogel disk was prepared. Characterization tests revealed the prepared artificial cornea had similar biocompatible and structural characteristics regarding the natural cornea. In current study, human amniotic membrane extract containing growth factors, cytokines, anti-inflammatory factors, and anti-angiogenic factors was prepared, nano-encapsulated in chitosan-dextran nanoparticles, and physically decorated on the poly(ε-caprolactone)-polyvinyl-alcohol artificial cornea. Physicochemical and biological characterizations revealed the nano-decorated artificial cornea has more biocompatibility than the unmodified one. Our study demonstrated the bioactive macromolecules loaded on chitosan-dextran nanoparticles enhanced the anti-angiogenic property of artificial cornea through the sustained release of anti-angiogenic factors such as thrombospondin-1, endostatin, and heparin sulfate proteoglycan. Real-time-PCR and flow-cytometry assessments elucidated the vascularization was inhibited through a decrease in the expression of cluster of differentiation 31 and von-Willebrand-Factor. Our study proposed the use of biocompatible artificial cornea could be a promising strategy in corneal transplantation.

The applications of heparin in vascular tissue engineering.

Cardiovascular diseases, among all diseases, are taking the most victims worldwide. Coronary artery occlusion, takes responsibility of about 30% of the yearly global deaths in the world (Heart Disease and Stroke Statistics 2017 At-a-Glance, 2017), raising the need for viable substitutes for cardiovascular tissues. Depending on a number of factors, blocked coronary arteries are now being replaced by autografts or stents. Since the autografts, as the gold standard coronary artery replacements, are not available in adequate quality and quantity, the demand for small diameter vascular substitute comparable to native vessels is rapidly growing. Synthetic grafts have been successfully approved for developing vascular replacements but regarding the special conditions in small-caliber vessels, their use is limited to large-diameter vascular tissue engineering. The major problems associated with the vascular tissue engineered grafts are thrombosis and intimal hyperplasia. Heparin, a negatively charged natural polysaccharide has been used in fabricating vascular grafts since it prevents protein fouling on the surfaces and most importantly, impeding thrombosis. Herein, we focused on heparin, as a multifunctional bioactive molecule that not only serves as an anticoagulant with frequent clinical use but also acts as an anti-inflammatory and angiogenic regulatory substance. We summarized heparin incorporation into stents and grafts and their applicability to restrain restenosis. Also, the applications of heparinzation of biomaterials and heparin mimetic polymers and different approaches invoked to improve heparin bioactivity have been reviewed. We summarized the methods of adding heparin to matrices as they were explained in the literature. We reviewed how heparin influences the biocompatibility of the scaffolds and discussed new advances about using heparin in small-diameter vascular tissue engineering.

Osteogenic Differentiation of MSCs on Fibronectin-Coated and nHA-Modified Scaffolds.

The increasing demand for biocompatible bone substitutes has made it a priority to tissue engineering and regenerative medicine scientists. Combination of minerals, growth factors, and extracellular matrix (ECM) proteins with nanofibrous scaffolds is a potential promising strategy for bone reconstruction and clinical applications. In this study, nanohydroxyapatite (nHA) was incorporated in electrospun nanofibrous polycaprolactone (PCL) scaffolds coated with fibronectin (Fn). The potential bone regeneration capacities of these scaffolds were evaluated in vitro and in vivo using mouse mesenchymal stem cells (mMSCs). The interconnected pores and proper mechanical characteristics of the fabricated electrospun PCL mats in combination with nHA and Fn provided suitable environment for cell attachment, proliferation, and enhanced osteogenic differentiation. The synergistic effect of Fn and nHA on the both in vitro and in vivo increase of calcium deposition was assessed by biochemical analysis. In addition, alkaline phosphatase (ALP) activity in nHA-incorporated PCL scaffold (PCL/nHA) and Fn-coated PCL/nHA (PCL/nHA/Fn) were significantly higher in comparison to the control group. Quantitative real-time reverse transcription polymerase chain reaction (RT-PCR) analyses of important bone-related genes (ALP, osteocalcin, osteopontin, and Runx2) revealed that Fn has additive effect on promoting the osteogenic differentiation. The aforementioned results indicated that nanofibrous PCL/nHA scaffold coated with Fn is a promising candidate for bone-tissue engineering applications.

Investigation of serum substance P status in patients with chronic pruritic skin lesions due to sulfur mustard: a cross-sectional study.

PURPOSE: Chronic cutaneous complications of sulfur mustard (SM) are quite common among intoxicated patients. Among these complications, pruritus represents the most frequent symptom which has significant influence on the quality of life (QoL). The present was undertaken to assess serum levels of substance P in patients who suffer from chronic pruritic lesions due to SM. METHODS: For this cross-sectional study, patients suffering from chronic SM-induced pruritic skin lesions (n = 40) and atopic dermatitis (AD)-induced pruritus (n = 20) were recruited. Healthy subjects (n = 10) with no dermatologic disorder were also recruited as control groups. Serum substance P was measured using an enzyme-linked immunosorbent assay. Pruritus severity was assessed using pruritus score and visual analogue scale (VAS). QoL was evaluated using the dermatology life quality index (DLQI). RESULTS: Significantly elevated serum concentrations of SP were found in the SM compared to the control (p < 0.001) and AD group (p < 0.001). Pruritus score was also higher in the SM compared to both control (p < 0.001) and AD groups (p < 0.001). While there was a higher VAS score in the SM vs. AD group (p = 0.019), no significant difference was observed for DLQI scores (p > 0.05). Significant correlations were found between serum SP and pruritus score in all assessed groups (p < 0.05). CONCLUSION: In light of the present findings, elevated SP levels might be regarded as an important contributor of SM-induced chronic pruritus and a potential target for reducing the symptoms.