International Online Survey on the Management of Patent Ductus Arteriosus.

INTRODUCTION: There is uncertainty and lack of consensus regarding optimal management of patent ductus arteriosus (PDA). We aimed to determine current clinical practice in PDA management across a range of different regions internationally. MATERIALS AND METHODS: We surveyed PDA management practices in neonatal intensive care units using a pre-piloted web-based survey, which was distributed to perinatal societies in 31 countries. The survey was available online from March 2018 to March 2019. RESULTS: There were 812 responses. The majority of clinicians (54%) did not have institutional protocols for PDA treatment, and 42% reported variable management within their own unit. Among infants <28 weeks (or <1,000 g), most clinicians (60%) treat symptomatically. Respondents in Australasia were more likely to treat PDA pre-symptomatically (44% vs. 18% all countries [OR 4.1; 95% CI 2.6-6.5; p < 0.001]), and respondents from North America were more likely to treat symptomatic PDA (67% vs. 60% all countries [OR 2.0; 95% CI 1.5-2.6; p < 0.001]). In infants ≥28 weeks (or ≥1,000 g), most clinicians (54%) treat symptomatically. Respondents in North America were more likely to treat PDAs in this group of infants conservatively (47% vs. 38% all countries [OR 2.3; 95% CI 1.7-3.2; p < 0.001]), and respondents from Asia were more likely to treat the PDA pre-symptomatically (21% vs. 7% all countries [OR 5.5; 95% CI 3.2-9.8; p < 0.001]). DISCUSSION/CONCLUSION: There were marked international differences in clinical practice, highlighting ongoing uncertainty and a lack of consensus regarding PDA management. An international conglomeration to coordinate research that prioritises and addresses these areas of contention is indicated.

The differing effects of a dual acting regulator on SIRT1.

SIRT1 is an NAD+-dependent protein deacetylase that has been shown to play a significant role in many biological pathways, such as insulin secretion, tumor formation, lipid metabolism, and neurodegeneration. There is great interest in understanding the regulation of SIRT1 to better understand SIRT1-related diseases and to better design therapeutic approaches that target SIRT1. There are many known protein and small molecule activators and inhibitors of SIRT1. One well-studied SIRT1 regulator, resveratrol, has historically been regarded as a SIRT1 activator, however, recent studies have shown that it can also act as an inhibitor depending on the identity of the peptide substrate. The inhibitory nature of resveratrol has yet to be studied in detail. Understanding the mechanism behind this dual behavior is crucial for assessing the potential side effects of STAC-based therapeutics. Here, we investigate the detailed mechanism of substrate-dependent SIRT1 regulation by resveratrol. We demonstrate that resveratrol alters the substrate recognition of SIRT1 by affecting the K M values without significantly impacting the catalytic rate (k cat). Furthermore, resveratrol destabilizes SIRT1 and extends its conformation, but the conformational changes differ between the activation and inhibition scenarios. We propose that resveratrol renders SIRT1 more flexible in the activation scenario, leading to increased activity, while in the inhibition scenario, it unravels the SIRT1 structure, compromising substrate recognition. Our findings highlight the importance of substrate identity in resveratrol-mediated SIRT1 regulation and provide insights into the allosteric control of SIRT1. This knowledge can guide the development of targeted therapeutics for diseases associated with dysregulated SIRT1 activity.