In vitro study on electrospun lecithin-based poly (L-lactic acid) scaffolds and their biocompatibility.

Lecithin is a natural mixture of phospholipids and neutral lipids, and plays a vital role in the maintenance of cell-membrane integrity for all of the basic biological processes.This study aimed to evaluate the adhesion and growth of bone marrow-derived mesenchymal stem cells (BMSCs) on the three-dimensional (3D) electrospun lecithin-containing poly (L-lactic acid) (PLLA) fibrous scaffolds. In this study, PLLA and 0-15% of lecithin (wt.%) were dissolved in methylene chloride and thoroughly mixed to fabricate fibrous scaffolds by electrospinning technique. Surface morphology and hydrophilic properties of the scaffolds were characterized by scanning electron microscopy (SEM) and water uptake, respectively. The cytocompatibility of electrospun scaffolds and their potential cytotoxic effects on cells were studied over 8 days by seeding rat BMSCs on the scaffolds of PLLA containing 0-15% lecithin. Then cell proliferation was tested by CCK-8 assay and cell injury was assessed by measuring the release of intracellular lactate dehydrogenase (LDH). And cell morphology was studied by Toluidine blue staining, propidium iodide staining and SEM. The hydrophilicity was dramatically increased with an increase of lecithin content in the modified PLLA/lecithin scaffolds, as determined by rate of water uptake. In addition, the results obtained from in vitro assays suggested that the electrospun PLLA/5%lecithin scaffolds could possess the optimal hydrophilicity, higher adhesion and proliferation of BMSCs than PLLA, and they also did not lead to any significant toxic effects to cells. Moreover, BMSCs on PLLA/5%lecithin scaffolds tended to maintain their phenotypic shape and integrate with the microfibers to form a 3D cellular network, indicating a favorable interaction between this electrospun lecithin-based scaffolds and cells. The study demonstrated that the electrospun PLLA/lecithin fibrous scaffolds showed much better hydrophilicity and biocompatibility by introducing lecithin into the polymer in comparison with pure PLLA, which would offer a promising strategy for constructing tissue engnineered blood vessel.

Effect of Low-Dose Vitamin K2 Supplementation on Bone Mineral Density in Middle-Aged and Elderly Chinese: A Randomized Controlled Study.

Previous studies indicated a positive effect of vitamin K2 (VK2) supplementation on bone turnover biomarkers and bone mineral density (BMD), but the doses varied, and few studies have focused on the difference between VK2 supplementation alone and in combination with calcium and vitamin D3. The aim of this study was to explore a low and effective dose of VK2 for improving BMD, and to examine whether the co-supplementation of VK2, calcium and vitamin D3 would bring greater effects. In this trial, a total of 311 community-dwelling men and postmenopausal women aged 50 and 75 years were randomly assigned to four groups, receiving placebo, 50 µg/day, 90 µg/day or co-supplementation with calcium (500 mg/day) and vitamin D3 (10 µg/day) for 1 year. At the endpoint, the bone loss of femoral neck was significantly lower in postmenopausal women in the two 90 µg groups (treatment × time, p = 0.006) compared with placebo, but no effects in men. Serum biomarkers cOC/ucOC ratio increased in the intervention groups (treatment × time, p < 0.001). VK2 supplementation in dose of 90 µg/day performed a significant effect on reducing bone loss in postmenopausal women, but in combination with calcium and vitamin D3 brought no additional effects.Trial registration This trial was registered at http://www.chictr.org.cn as chiCTR1800019240.