Biochemistry

Angiogenesis is a crucial step in tissue regeneration and repair. Biomaterials that allow or promote angiogenesis are thus beneficial. In this study, angiogenic properties of salt-leached silk fibroin (SF) scaffolds seeded with human adipose stem cells (hADSCs) were studied using chick chorioallantoic membrane (CAM) as a model. The hADSC-seeded SF scaffolds (SF-hADSC) with the porosity of 77.34 ± 6.96% and the pore diameter of 513.95 ± 4.99 µm were implanted on the CAM of chick embryos that were on an embryonic day 8 (E8) of development. The SF-hADSC scaffolds induced a spoke-wheel pattern of capillary network indicative of angiogenesis, which was evident since E11. Moreover, the ingrowth of blood vessels into the scaffolds was seen in histological sections. The unseeded scaffolds induced the same extent of angiogenesis later on E14. By contrast, the control group could not induce the same extent of angiogenesis. In vitro cytotoxicity tests and in vivo angioirritative study reaffirmed the biocompatibility of the scaffolds. This work highlighted that the biocompatible SF-hADSC scaffolds accelerate angiogenesis, and hence they can be a promising biomaterial for the regeneration of tissues that require angiogenesis.

The complete regeneration of periodontal tissues following current periodontal therapy remain challenging and unpredictable. Nucleoside-modified messenger RNA (mRNA) technology can be a promising novel platform in regenerative medicine. The aims of this study were to evaluate whether mRNA encoding vascular endothelial growth factor (VEGF) could induce VEGF production in human periodontal ligament cells (PDLCs) and this translated protein function by promoting in vivo blood vessel formation using chorioallantoic membrane (CAM) assay. Isolated PDLCs from healthy periodontal tissue were transfected with pseudouridine modified mRNA encoding VEGF (VEGF mRNA) complexed with a transfecting agent, Lipofectamine 2000 (L2000) and L2000 alone (control). Supernatants collected at 24 hours (h) after transfection were evaluated for protein production by ELISA and cell viability by Alamar Blue assay. The supernatants of the VEGF mRNA-L2000, L2000 (control) and DPBS (negative control) were applied on filter papers, individually placed these grafts on to the CAM surface through the window on day 8 of embryonic development (E8) and incubated for another three days. Angiogenesis assessment, counting numbers of blood vessels convergence to the grafts, was carried out by photographed with stereomicroscopic on E8 and E11. The result showed that PDLCs, transfected with mRNA encoding VEGF, produced high level of VEGF protein than controls at 24 h. The transfection of mRNA encoding VEGF showed negligible effect on PDLC viability. When supernatants were applied in CAM assay, translated protein VEGF protein was able to significantly induce blood vessel formation (p < 0.001). In conclusion, modified mRNA encoding VEGF promoted VEGF production and had angiogenic properties, increased blood vessel formation in the CAM. Thus, this mRNA platform technology may allow future application as a novel therapeutic platform for periodontal regeneration.

The global population has been exposed to the novel pandemic H1N1 influenza virus since mid March 2009, causing the expansion of respiratory illness around the world, including Thailand. To evaluate the antibody titers against human pandemic influenza (H1N1) in Thai people with influenza-like illness (ILI), 45 paired serum samples (acute and convalescent) were subjected to hemagglutination inhibition (HI) test and real-time RT-PCR. Most serum samples of ILI patients positive by real-time RT-PCR displayed an at least four-fold antibody increase of HI titers against pandemic influenza (H1N1). In addition, to determine cross-reactivity with human seasonal H1N1 influenza, viral antigen from the seasonal H1N1 was used to detect antibody against seasonal H1N1 influenza and all sera showed negative results. We also studied the single sera samples from the high risk medical personals collected before and after the pandemic influenza (HIN1) outbreaks for antibodies against seasonal H3 influe...