Search

Cyclic ADP‐ribose (cADPR) has emerged as a calcium‐regulating second messenger in smooth muscle cells. CD38 protein possesses ADP‐ribosyl cyclase and cADPR hydrolase activities and mediates cADPR synthesis and degradation. We have previously shown that CD38 expression is regulated by estrogen and progesterone in the myometrium. Considering hormonal regulation in gestation, the objective of the present study was to determine the role of CD38/cADPR signaling in the regulation of intracellular calcium upon contractile agonist stimulation using immortalized pregnant human myometrial (PHM1) cells. Western blot, immunofluorescence, and biochemical studies confirmed CD38 expression and the presence of ADP‐ribosyl cyclase (2.6 ± 0.1 pmol/mg) and cADPR hydrolase (26.8 ± 6.8 nmoles/mg/h) activities on the PHM1 cell membrane. Oxytocin, PGF2α, and ET‐1 elicited [Ca2+]i responses, and 8‐Br‐cADPR, a cADPR antagonist significantly attenuated agonist‐induced [Ca2+]i responses between 20% and 46% in average. The findings suggest that uterine contractile agonists mediate their effects in part through CD38/cADPR signaling to increase [Ca2+]i and presumably uterine contraction. As studies in humans are limited by the availability of myometrium from healthy donors, PHM1 cells form an in vitro model to study human myometrium. [ABSTRACT FROM AUTHOR]

Gold nanoparticles (GNPs) have been widely used in medicine such as imaging, drug delivery and therapeutics due to their multifunctional properties. Alterations in neuronal function may contribute to various neurological diseases. Transferrin plays a primary role in iron transportation and delivery and has recently been utilized for drug delivery to the brain. We have investigated effects of transferrin-conjugated GNPs (Tf-GNPs) on anxiety and locomotor behavior in vivo and also hippocampal neuronal activity ex vivo. Electrophysiological effects of Tf-GNP on hippocampal neurons were determined by patch clamp method. Fifteen male young adult C57BL/6 mice were randomly divided into three groups as control (200 µL PBS), GNP (bare GNP; 2.2 μg/g in PBS) and Tf-GNPs (2.2 μg/g Tf-GNP). Animals intraperitoneally received the respective treatments for seven consecutive days and were subjected to elevated plus maze (EPM) and open field tests (OFT). Ex vivo, firing frequency of the neurons significantly increased by GNP treatment (p < 0.001). In vivo, animals in Tf-GNP group showed significantly longer distance in open arms but significantly lower number of entries to the open arms in EPM (p < 0.05). Mice received bare GNPs had significantly higher locomotor activity in OFT (p < 0.05), while Tf-GNP did not alter the locomotor activity significantly (p = 0.051). Animals in Tf-GNP group spent significantly longer time in the peripheral zone in OFT (p < 0.05). The present findings have shown that Tf-GNP induces anxiety-like behavior without altering spontaneous firing rate of hippocampal neurons. We suggest that neurobiological effects of Tf-GNP should be pre-determined before using in medical applications. [ABSTRACT FROM AUTHOR]

Background: Regulation is part of the technology innovation process and has a key role within the lifecycle of a medical device aiming at ensuring effectiveness and safety for users (1). Ever-increasing regulatory requirements (e.g., the Regulation MDR (EU) 2017/745) impact on the development of novel and already approved systems (2, 3). Debating and raising awareness is important since it can improve the transfer of knowledge and expertise among the relevant stakeholders. Thus, the implementation of a survey to explore knowledge and perception of the regulatory framework of medical devices for the assessment of vascular age can be helpful for the involved community. Methods: A multidisciplinary team including clinicians, researchers and developers from VascAgeNet was established to design and implement a digital questionnaire. A secure, open-source, two-factor authentication system for generation, distribution, and data collection of the survey supported by the European Commission (EUSurvey, https://ec. europa. eu/eusur vey) was adopted. Results: The questionnaire has received ethical clearance by National Council of Research, Italy (Notification 0063984/2021) and University College London (17999/002) Research Ethics Committees and is being distributed digitally (e.g., within VascAgeNet, Artery Society etc.). The anonymous questionnaire is available at https://ec. europa. eu/eusur vey/runner/REGUL ATORY Surve y2022 or by scanning the QR code below, it takes approximately 10 min to complete. Conclusions: A survey related to regulation and medical devices for vascular ageing assessment has been developed and is available for the community. The results could inspire concrete actions reducing gap between research and clinical practice. [ABSTRACT FROM AUTHOR]

Small artery remodeling involves matrix reorganization, but may also encompass changed smooth muscle cell biomechanical properties. Here we study the temporal relationship between such contractile plasticity and matrix remodeling in small rat mesenteric arteries subjected to 1 or 3 days of altered flow or acute interventions on matrix structure; cross-linking by transglutaminase and matrix digestion by elastase. Diameter-tension relations were made in the passive state and upon full activation (125 mM K+ and 10-5 M norepinephrine). In low flow (LF), inward matrix remodeling occurred after 1 day, when the distended diameter at full dilation (D100 ) was reduced from 351 + 15 µm to 299 + 14 µm (SEM, n=8, p <0.05). The optimal diameter for force development(Dopt) was reduced after 3 days, from 291 + 10 µm to 247 + 5 µm (LF, p <0.05). As a result, a mismatch of Dopt/D100 existed after 1 day of LF, which normalized after 3 days. Dynamics of contraction were studied following quick isometric release by 0.2·D100; tension recovery was faster in anatomically smaller vessels following normal flow. This association was partly lost after 1 day of LF, while after 3 days the vessels became not only smaller but also faster, re-establishing this association. High flow vessels demonstrated similar contractile plasticity. Active diameter-tension relations at low distension did not change following transglutaminase or elastase. However, at high distension, any alteration in passive tension coincided with an opposite change in active tension. These data demonstrate an intrinsic interaction between passive and active biomechanics that occurs instantaneously during matrix remodeling at high distensions while contractile plasticity lags matrix remodeling after flow interventions. [ABSTRACT FROM AUTHOR]

Increasing evidence shows that sex hormones exert a protective effect on the vasculature, especially in the regulation of the active vasomotor responses. However, whether sex hormones affect vascular remodelling is currently unclear. In the present study, we tested the hypothesis that testosterone in males and β-oestradiol in females prevent inward remodelling, possibly through inhibition of cross-linking activity induced by enzymes of the TG (transglutaminase) family. Small mesenteric arteries were isolated from male and female Wistar rats. Dose-dependent relaxation to testosterone and β-oestradiol was inhibited by the NO synthase inhibitor L-NAME (NG-nitro-L-arginine methyl ester), confirming that these hormones induce NO release. When arteries were cannulated, pressurized and kept in organ culture with ET-1 (endothelin-1) for 3 days we observed strong vasoconstriction and inward remodelling. Remodelling was significantly inhibited by testosterone in males, and by β-oestradiol in females. This preventive effect of sex hormones was not observed in the presence of L-NAME. Inward remodelling was also reduced by the inhibitor of TG L682.777, both in males and females. In arteries from female rats, ET-1 increased TG activity, and this effect was prevented by β-oestradiol. L-NAME induced a significant increase in TG activity in the presence of sex hormones in arteries from both genders. We conclude that testosterone and β-oestradiol prevent constriction-induced inward remodelling. Inward remodelling, both in males and females, depends on NO and TG activity. In females, inhibition of inward remodelling could be mediated by NO-mediated inhibition of TG activity.