Worldwide and Country-Specific Impact of the COVID-19 Pandemic on Heart Transplantation Volumes: A Longitudinal Analysis of 2020 and 2021.

COVID-19 pandemic hampered operational efficiency of heart transplant (HT) programs worldwide. Little is known about the global and country-specific changes in HT volumes during the pandemic years 2020-2021. We aimed to describe the global and country-level impact of the COVID-19 pandemic on HT volumes in 2020-2021. This is a cross-sectional study of the Global Observatory on Donation and Transplantation, including the years 2019-2021. Among 60 countries that reported HT data in the years 2019-2020, we analyzed 52 countries with ≥1 transplant during each year. Overall, the number of HTs decreased during 2020 by 9.3% (1.82 to 1.65 PMP). While 75% (n = 39/52) of countries experienced a decrease in HT volumes in 2020, volumes were maintained/increased in the remaining countries. Countries with maintained HT volumes had a higher organ donation rate in 2020 compared to those with decreased volumes (P = 0.03), the only significant predictor of change in HT volumes (P = 0.005). In 2021, a 6.6% recovery from the previous year's drop in global HT rate was noticed, reaching 1.76 HT PMP. Only 1 in 5 countries with reduced volumes in 2020 recovered their baseline volumes in 2021. Only 30.8% of countries with maintained volumes in 2020 had continued growth in HT volumes in 2021. The latter group encompassed the United States of America, the Netherlands, Poland, and Portugal. Further work should define underlying causes of this heterogeneity in HT volume during the pandemic. Identifying policies and practices that helped certain countries mitigate the effect of the pandemic on HT activities may help other countries during similar health crises in the future.

Cytotoxicity and Antibiofilm Activity of Silver-Polypropylene Nanocomposites.

The development of biocompatible nanomaterials that interface with human skin and tissue is critical for advancing prosthetics and other therapeutic medical needs. In this perspective, the development of nanoparticles with cytotoxicity and antibiofilm properties and biocompatibility characteristics are important. Metallic silver (Ag) exhibits good biocompatibility, but it is often challenging to integrate it into a nanocomposite without compromising its antibiofilm properties for optimal applications. In this study, new polymer nanocomposites (PNCs) with ultra-low filling content (0.0023-0.046 wt%) of Ag nanoplates were manufactured and tested. The cytotoxicity and antibiofilm activity of different composites with polypropylene (PP) matrix were examined. At first, PNCs surface were analyzed by means of AFM (atomic force microscopy) with phase contrast evaluation and FTIR (Fourier-transform infrared spectroscopy) to study the Ag nanoplates distribution. Subsequently, the cytotoxicity and growth properties of biofilms were assessed by MTT assay protocol and detection of nitric oxide radicals. Antibacterial and antibiofilm activities were measured against Gram-positive bacteria (Staphylococcus aureus) and Gram-negative bacteria (K. pneumoniae). The PNCs with silver exhibited antibiofilm activity although they did not inhibit regular planktonic bacterial growth. Moreover, the PNCs were not cytotoxic to mammalian cells and did not induce significant immune response. These features reveal the potential of the PNCs developed in this study for usage in fabrication of prosthetics and other smart structures for biomedical applications.