The SARS-CoV2 envelope differs from host cells, exposes procoagulant lipids, and is disrupted in vivo by oral rinses.

The lipid envelope of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is an essential component of the virus; however, its molecular composition is undetermined. Addressing this knowledge gap could support the design of antiviral agents as well as further our understanding of viral-host protein interactions, infectivity, pathogenicity, and innate immune system clearance. Lipidomics revealed that the virus envelope comprised mainly phospholipids (PLs), with some cholesterol and sphingolipids, and with cholesterol/phospholipid ratio similar to lysosomes. Unlike cellular membranes, procoagulant amino-PLs were present on the external side of the viral envelope at levels exceeding those on activated platelets. Accordingly, virions directly promoted blood coagulation. To investigate whether these differences could enable selective targeting of the viral envelope in vivo, we tested whether oral rinses containing lipid-disrupting chemicals could reduce infectivity. Products containing PL-disrupting surfactants (such as cetylpyridinium chloride) met European virucidal standards in vitro; however, components that altered the critical micelle concentration reduced efficacy, and products containing essential oils, povidone-iodine, or chlorhexidine were ineffective. This result was recapitulated in vivo, where a 30-s oral rinse with cetylpyridinium chloride mouthwash eliminated live virus in the oral cavity of patients with coronavirus disease 19 for at least 1 h, whereas povidone-iodine and saline mouthwashes were ineffective. We conclude that the SARS-CoV-2 lipid envelope i) is distinct from the host plasma membrane, which may enable design of selective antiviral approaches; ii) contains exposed phosphatidylethanolamine and phosphatidylserine, which may influence thrombosis, pathogenicity, and inflammation; and iii) can be selectively targeted in vivo by specific oral rinses.

A randomised controlled trial to compare the efficacy of an aluminium lactate/potassium nitrate/hydroxylapatite toothpaste with a control toothpaste for the prevention of dentine hypersensitivity

ObjectivesTo determine the efficacy of a cosmetic aluminium lactate/potassium nitrate/hydroxylapatite toothpaste for the reduction of dentine hypersensitivity (DH) pain as compared to a control toothpaste containing potassium nitrate.MethodsThe study was a randomised, examiner-blind, two treatment arm, parallel controlled trial in healthy adults with at least 2 sensitive teeth (Schiff >2). At baseline, immediately after treatment and at 7 and 14 days of twice-daily brushing of the test or control toothpaste the sensitivity of 2 test teeth was measured following iced-water (Schiff and VAS) and tactile (Yeaple probe) stimuli, and a whole mouth plaque score was obtained. Participants also completed a whole-mouth VAS and DHEQ15 quality of life questionnaire at baseline, 7 and 14 days.ResultsBoth toothpastes reduced DH in test teeth, but pain reduction in the test group was significantly better at all timepoints and by all measures (p = 0.005, tooth-level VAS immediately after brushing;p < 0.001 all other comparisons). There was a relative risk reduction of Schiff sensitivity of 55 % immediately after brushing which rose to 81 % after 7 and 88.6 % after 14 days (all p < 0.001). There were no differences in plaque, whole mouth VAS or DHEQ15 scores at any time point.ConclusionThis study demonstrated the efficacy of an aluminium lactate/potassium nitrate/hydroxylapatite toothpaste compared to a potassium nitrate control toothpaste for the prevention of dentine hypersensitivity both immediately and over a 2 week period. This agent appears to have potential for pain alleviation from the common oral pain condition of DH and further research is warranted.Clinical significanceDH pain, whilst transient in nature, is arresting in magnitude, affecting quality of life. Daily application of efficacious toothpastes can relieve DH pain however, as yet, there is no gold standard treatment. The results of this study support further investigation of an aluminium lactate/potassium nitrate/hydroxylapatite toothpaste for DH management.