The effect of Nano-liposomal sodium nitrite on smooth muscle cell growth in a tissue-engineered small-diameter vascular graft.

BACKGROUND: Nitric oxide is a chemical agent produced by endothelial cells in a healthy blood vessel, inhibiting the overgrowth of vascular smooth muscle cells and regulating vessel tone. Liposomes are biocompatible and biodegradable drug carriers with a similar structure to cell bilayer phospholipid membrane that can be used as useful nitric oxide carriers in vascular grafts. METHOD: Using a custom-designed apparatus, the sheep carotid arteries were decellularized while still maintaining important components of the vascular extracellular matrix (ECM), allowing them to be used as small-diameter vascular grafts. A chemical signal of sodium nitrite was applied to control smooth muscle cells' behavior under static and dynamic cell culture conditions. The thin film hydration approach was used to create nano-liposomes, which were then used as sodium nitrite carriers to control the drug release rate and enhance the amount of drug loaded into the liposomes. RESULTS: The ratio of 80:20:2 for DPPC: Cholesterol: PEG was determined as the optimum formulation of the liposome structure with high drug encapsulation efficiency (98%) and optimum drug release rate (the drug release rate was 40%, 65%, and 83% after 24, 48, and 72 h, respectively). MTT assay results showed an improvement in endothelial cell proliferation in the presence of nano-liposomal sodium nitrite (LNS) at the concentration of 0.5 µg/mL. Using a suitable concentration of liposomal sodium nitrite (0.5 µg/mL) put onto the constructed scaffold resulted in the controllable development of smooth muscle cells in the experiment. The culture of smooth muscle cells in a pulsatile perfusion bioreactor indicated that in the presence of synthesized liposomal sodium nitrite, the overgrowth of smooth muscle cells was inhibited in dynamic cell culture conditions. The mechanical properties of ECM graft were measured, and a multi-scale model with an accuracy of 83% was proposed to predict mechanical properties successfully. CONCLUSION: The liposomal drug-loaded small-diameter vascular graft can prevent the overgrowth of SMCs and the formation of intimal hyperplasia in the graft. Aside from that, the effect of LNS on endothelial has the potential to stimulate endothelial cell proliferation and re-endothelialization.

A case of recurrent pneumothorax and skin lesions diagnosed with Birt-Hogg-Dubé.

Birt-Hogg-Dubé (BHD) syndrome is an autosomal dominant disease that is manifested as benign cutaneous tumors, multiple lung parenchymal cysts and an increased risk of renal cancer. Its symptoms usually do not appear until adulthood. We report a patient who was admitted with recurrent pneumothorax. Discovering typical cutaneous lesions accompanied with a history of the same condition in his son, BHD syndrome was diagnosed.

A biomaterials approach to Schwann cell development in neural tissue engineering.

Schwann cells, in addition to forming myelin sheaths, have pivotal roles in regeneration of injured axons in the peripheral nervous system such as producing a natural permissive conduit between distal and proximal stumps and secreting nerve growth factors. Due to the atrophy and senescence of Schwann cells in long nerve gap, and the need to ensure the presence of nerve growth factors and basal lamina tubes for axon regeneration in a critical time, injection of Schwann cells with the aid of an engineered conduit seems to be an effective approach to induce axon regrowth. Stem cells with high differentiation and proliferation capability can provide an adequate number of Schwann cells in healthy state for regeneration purposes. Guidance of stem cells differentiation into desired lineages, control of implanted Schwann cells fate, maintenance of nerve growth factors expression, and guidance of axon regrowth are possible with the aid of biomaterials with appropriate chemical, physical, and mechanical properties. Biomaterials' surface chemistry and biomolecules interacting with cells' receptors initiate specific intracellular signaling cascades and direct cells fate. In addition, biomaterials' surface topography in association with cells contact area, focal adhesion, and cytoskeletal remodeling by mechanotransduction process influences cells behavior and induces specific differentiation. The main objective of this review is to investigate the chemical, topographical, and mechanical properties of biomaterials which influence the fate of Schwann cells and the nerve regeneration process.

Effects of enzymatic extraction on anthocyanins yield of saffron tepals (Crocos sativus) along with its color properties and structural stability.

An aqueous solution of Pectinex (containing cellulase, hemicellulase, and pectinase) at 1%, 2.5%, 5%, 7%, and 10% concentrations and 40°C was used to extract anthocyanins (Acys) of saffron tepals at 20, 40, 60, 120 and 180 min reaction times and compared with ethanol solvent under similar conditions. The Acys of the Pectinex solution reached 6.7 mg/g of tepal powder (∼40% more than the ethanol method) when the enzyme concentrations and extraction times were, respectively, 5% and 60 min. The Acys of aqueous enzymes had three times slower degradation rates and 50% more attractive chroma color than the ones recovered by ethanol solution after 3 h of extraction time. Additionally, the Acys of the ethanol solution lost its content sharply (>45%) and its chroma changed quickly (due to the browning and polymerization). High performance liquid chromatography (HPLC) analysis showed that Acys extracted with mixed enzymes had about 80% more cyanidin 3-glucosides and 20% less pelargonidin 3,5-glucosides than with the ethanol method. Most probably, the high content of cyanidin 3-glycosides in enzyme-extracted Acys of saffron tepals was the key factor for its high stability.

Interaction of methocarbamol and yeast sucrase induces enzyme inhibition.

BACKGROUND: Methocarbamol is a skeletal muscle relaxant and is widely used to relieve pain in muscles. Many drugs may have interactions with each other when used at the same time. Yeast sucrase is taken as a drug by patients with congenital sucrase-isomaltase deficiency (CSID). METHODS: In this study, the interaction between methocarbamol and yeast sucrase was investigated. RESULTS: Our results showed that methocarbamol can inhibit sucrase activity and reduce the maximum reaction velocity (Vmax) of the enzyme by a non-competitive pattern. Measurement of IC50 and Ki of the drug revealed that methocarbamol did not bind the enzyme with high affinity. Fluorescence measurement showed that the drug binds to free enzyme and enzyme-substrate complexes that were accompanied by structural changes on the enzyme. Guaifenesin, which has a similar structure to methocarbamol, does not affect the activity of sucrase. CONCLUSIONS: Methocarbamol inhibits sucrase activity and its carbamate group plays a main role in the binding of drug to sucrase.