Background The effect of chronic use of renin–angiotensin–aldosterone system (RAAS) inhibitors on the severity of COVID-19 infection is still unclear in patients with hypertension. We aimed to investigate the association between chronic use of angiotensin-converting enzyme inhibitors (ACEIs) or angiotensin II receptor blockers (ARBs) and COVID-19 related outcomes in hypertensive patients. Methods A single center study was conducted on 133 consecutive hypertensive subjects presenting to the Emergency Department with acute respiratory symptoms and/or fever who were diagnosed with COVID-19 infection between 9th and 31st March 2020. Results All patients were grouped according to their chronic antihypertensive medications (ACEIs, N=40; ARBs, N=42; not on RAAS inhibitors, N=51). There was no statistical difference between ACEIs and ARBs groups in terms of hospital admission rate, oxygen therapy and need for non-invasive ventilation. Patients chronically treated with RAAS inhibitors showed a significantly lower rate of admission to semi-intensive/intensive care units, when compared to the non-RAAS population (odds ratio [OR] 0.25, CI95% 0.09-0.66 p=0.006). Similarly, the risk of mortality was lower in the former group, although not reaching statistical significance (OR 0.56, CI95% 0.17-1.83, p=0.341). Conclusions Our data suggest that chronic use of RAAS inhibitors does not negatively affect clinical course of COVID-19 in hypertensive patients. Further studies are needed to confirm this finding and determine whether RAAS inhibitors may have a protective effect on COVID 19-related morbidity and mortality.

Background: Mutations leading to changes in properties, regulation, or expression of connexin-made channels have been implicated in 28 distinct human hereditary diseases. Eight of these result from variants of connexin 26 (Cx26), a protein critically involved in cell-cell signaling in the inner ear and skin. Lack of non-toxic drugs with defined mechanisms of action poses a serious obstacle to therapeutic interventions for diseases caused by mutant connexins. In particular, molecules that specifically modulate connexin hemichannel function without affecting gap junction channels are considered of primary importance for the study of connexin hemichannel role in physiological as well as pathological conditions. Monoclonal antibodies developed in the last three decades have become the most important class of therapeutic biologicals. Recombinant methods permit rapid selection and improvement of monoclonal antibodies from libraries with large diversity.Methods: By screening a combinatorial library of human single-chain fragment variable (scFv) antibodies expressed in phage, we identified a candidate that binds an extracellular epitope of Cx26. We characterized antibody action using a variety of biochemical and biophysical assays in HeLa cells, organotypic cultures of mouse cochlea and human keratinocyte-derived cells.Results: We determined that the antibody is a remarkably efficient, non-toxic, and completely reversible inhibitor of hemichannels formed by connexin 26 and does not affect direct cell-cell communication via gap junction channels. Importantly, we also demonstrate that the antibody efficiently inhibits hyperative mutant Cx26 hemichannels implicated in autosomal dominant non-syndromic hearing impairment accompanied by keratitis and hystrix-like ichthyosis-deafness (KID/HID) syndrome. We solved the crystal structure of the antibody, identified residues that are critical for binding and used molecular dynamics to uncover its mechanism of action.Conclusions: Although further studies will be necessary to validate the effect of the antibody in vivo, the methodology described here can be extended to select antibodies against hemichannels composed by other connexin isoforms and, consequently, to target other pathologies associated with hyperactive hemichannels. Our study highlights the potential of this approach and identifies connexins as therapeutic targets addressable by screening phage display libraries expressing human randomized antibodies.

Blood pressure (BP) is characterized by continuous dynamic and spontaneous oscillations occurring over lifetime and defining the so-called blood pressure variability (BPV). BPV has been associated with target organ damage, cardiovascular (CV) risk and death, suggesting the use of BPV as a new target in hypertension management in addition to mean BP values lowering. The purpose of the review is to focus on the therapeutic implications of BPV and summarize the effects of different drug classes on various types of BPV. Despite most first-line antihypertensive medications contribute to reduce both short and long term BPV, calcium channel blockers (CCBs) as monotherapy or fixed-combination therapy appear to be the most effective on BPV control. Further randomized interventional trials are needed to investigate which drug combinations are most appropriate according to patient CV risk stratification, in order to improve their CV outcomes.

Background Numerous currently incurable human diseases have been causally linked to mutations in connexin (Cx) genes. In several instances, pathological mutations generate abnormally active Cx hemichannels, referred to also as “leaky” hemichannels. The goal of this study was to assay the in vivo efficacy of a potent antagonist antibody targeting Cx hemichannels. Methods We employed the antibody to treat Cx30 A88V/A88V adult mutant mice, the only available animal model of Clouston syndrome, a rare orphan disease caused by Cx30 p.A88V leaky hemichannels. To gain mechanistic insight into antibody action, we also performed patch clamp recordings, Ca 2+ imaging and ATP release assay in vitro . Findings Two weeks of antibody treatment sufficed to repress cell hyperproliferation in skin and reduce hypertrophic sebaceous glands (SGs) to wild type (wt) levels. These effects were obtained whether mutant mice were treated topically, by application of an antibody cream formulation, or systemically, by intraperitoneal antibody injection. Experiments with mouse primary keratinocytes and HaCaT cells revealed the antibody blocked Ca 2+ influx and diminished ATP release through leaky Cx30 p.A88V hemichannels. Interpretation Our results show anti-Cx antibody treatment was effective in vivo and sufficient to counteract the effects of pathological connexin expression in Cx30 A88V/A88V mice. In vitro experiments suggest antibodies gained control over leaky hemichannels and contributed to restoring epidermal homeostasis. Therefore, regulating cell physiology by antibodies targeting the extracellular domain of Cxs may enforce an entirely new therapeutic strategy. These findings support the further development of antibodies as drugs to address unmet medical needs for Cx-related diseases. Fund Fondazione Telethon, GGP19148; University of Padova, SID/BIRD187130; Consiglio Nazionale delle Ricerche, DSB.AD008.370.003\TERABIO-IBCN; National Science Foundation of China, 31770776; Science and Technology Commission of Shanghai Municipality, 16DZ1910200.