Oxidative and Fibrinolytic Mechanisms: Two Important Processes to Consider in Platelet Storage

Objective: Platelet-rich plasma (PRP) is used in multiple coagulation disorders. Its therapeutic effectiveness relies on technical procedures related to PRP procurement and preservation because free radicals induce platelet activation and aging. This work aims to elucidate the oxidative mechanisms involved in activation of platelets obtained from PRP during storage. Materials and Methods: One hundred ten PRP batches were obtained from healthy donors and kept under stirring at a temperature of 20-24 °C. Protein extraction was performed from platelet homogenates and plasma at different times of storage from day 1 to 20. The activities of antioxidant markers such as catalase (CAT), superoxide dismutase, and ceruloplasmin, as well as fibrinolytic protein activity metalloproteases 2 and 3, plasmin, and urokinase plasminogen activator, were analyzed by zymography assays. Oxidized proteins were also determined. Results: Significant activity of antioxidant enzymes and fibrinolytic molecules was observed on day 5 of storage in PRP homogenates, which increased over time and was concomitantly correlated with oxidized protein levels. Reverse enzymatic activity patterns were observed in plasma, except for CAT, which remained unchanged. Conclusion: Storage conditions of platelets from PRP for up to 5 days induced in vitro platelet activation by oxidative damage and proteolysis. This finding confirms the need for proper management of these blood products to preserve their viability and functionality.

Novel Triamcinolone Acetonide-Loaded Liposomes Topical Formulation for the Treatment of Cystoid Macular Edema After Cataract Surgery: A Pilot Study.

PURPOSE: To report tolerability, safety, and efficacy of a topical triamcinolone acetonide-loaded liposomes formulation (TA-LF) in targeting the macular area in patients with refractory pseudophakic cystoid macular edema (PCME). METHODS: For tolerability, safety and efficacy evaluation, 12 eyes of 12 patients with refractory PCME were exposed to one drop of TA-LF (TA at 0.2%) every 2 h for 90 days or until best-corrected visual acuity (BCVA) was achieved. Intraocular pressure (IOP), slit lamp examination, and central foveal thickness (CFT) were analyzed at every visit. RESULTS: Patients with refractory PCME under TA-LF therapy showed a significant improvement in BVCA and CFT without significant IOP modification (P = 0.94). On average CFT decreased to 206.75 ± 135.72 µm and BCVA improved to 20.08 ± 10.35 letters (P < 0.0005). BCVA was achieved at 10.58 ± 6.70 weeks (range 2-18). TA-LF was well tolerated in all cases. Neither ocular surface abnormalities nor adverse events were recorded. CONCLUSION: TA-LF was well tolerated and improved BCVA and CFT on patients with refractory PCME.

Interferon-α Silencing by Small Interference RNA Increases Adenovirus Transduction and Transgene Expression in Huh7 Cells.

Adenoviruses are the most common vectors used in clinical trials of gene therapy. In 2017, 21.2% of clinical trials used rAds as vectors. Systemic administration of rAds results in high tropism in the liver. Interferon types α and ß are the major antiviral cytokines which orchestrate the host's immune response against rAd, limiting therapeutic gene expression and preventing subsequent vector administration. siRNA is small double-strand RNAs that temporally inhibit the expression of a specific gene. The aim is to evaluate the effect of IFN-α blocking by a specific siRNA on Ad-GFP transduction and on transgene expression in Huh7 cells in culture. Huh7 cells were cultured in DMEM and transfected with 70 nM of siRNA-IFN-α. Six hours later, the cells were exposed to 1 × 109 vp/ml of rAd-GFP for 24 h. Expression of IFN-α, TNF-α and the PKR gene was determined by RT-qPCR. Percentage of transduction was analyzed by flow cytometry and by qPCR. GFP expression was determined by western blot. 70 nM of siRNA-IFN-α inhibited 96% of IFN-α and 65% of TNF-α gene expression compared to an irrelevant siRNA. Percentage of transduction and transgene expression increased in these cells compared to an irrelevant siRNA. Inhibition of IFN-α expression by siRNA-IFN-α enabled a higher level of transduction and transgene expression GFP, highlighting the role of IFN-α in the elimination of adenovirus in transduced cells and thus suggesting that its inhibition could be an important strategy for gene therapy in clinical trials using adenovirus as a vector directed to liver diseases.