Dynamics of antibody response to CoronaVac vaccine.

CoronaVac was the first vaccine approved in Brazil for use in healthcare workers (HCWs). However, there is limited information about it, with little long-term evidence on post-vaccination antibody persistence. This study evaluated the antibody response to SARS-CoV-2 in 1237 HCWs after the first (1D), second dose (2D), and 6 months postvaccination (6mA2D) with CoronaVac. The seropositivity was 88% at 1D, increasing to 99.8% at 2D, but decreasing to 97.9% at 6mA2D, which was also observed at the analyzed antibody levels. Interestingly, the levels in females were higher than males, and we found a positive correlation with previous SARS-CoV-2 infection. Participants with comorbidities had lower levels suggesting the need to monitor for a potential booster dose. Our findings suggest that CoronaVac induced a robust antibody response that wanes significantly over time. Further longitudinal studies are needed to identify whether the antibodies will decline or plateau at a lower level.

The Wound Healing Property of N-Methyl-(2S,4R)-trans-4-Hydroxy-L-Proline from Sideroxylon obtusifolium is Related to its Anti-Inflammatory and Antioxidant Actions.

Wound healing involves the interaction of blood cells, proteins, proteases, growth factors, and extracellular matrix components. Inflammation is one of the first events occurring during this process. Previously, we showed that the N-Methyl-(2S,4R)-trans-4-Hydroxy-L-Proline (NMP) from Sideroxylon obtusifolium leaves (a Brazilian medicinal species) presents an anti-inflammatory action. Considering inflammation as an important event in the wound healing process, the objectives were to investigate the topical effects of the NMP gel on a mice wound-induced model. Male Swiss mice were divided into 4 groups: Sham (surgical procedure only), Control (gel-base treated), and 3% or 10% NMP gel-treated groups. Measurements of wound areas and microscopic analyses (HE [hematoxylin-eosin] and PSR [picrosirius red] stainings) were carried out, at the 7th and 12th, days after the wound induction. Furthermore, immunohistochemical assays for iNOS (inducible nitric oxide synthase) and COX-2 (cyclooxygenase-2) and biochemical measurements for TBARS (thiobarbituric acid reactive substances), GSH (glutathione), and myeloperoxidase (MPO) were also performed, at the second day after the wound induction. The work showed that NMP decreases the wound areas, after topical application, relatively to the Sham and Control groups. In addition, microscopic alterations were reduced and collagen deposition was increased, at the 7th and 12th days, in the 10% NMP group. While iNOS and COX-2 immunostainings and GSH contents increased, in relation to the Sham and Control groups, TBARS and MPO decreased. Altogether, the results showed NMP to improve the wound healing process, by upregulating iNOS and COX-2 activities, reducing lipid peroxidation and MPO activity, and increasing GSH contents. In addition, NMP certainly contributes to the increased collagen deposition. These data may stimulate translational studies dealing with the possible use of NMP from Sideroxylon obtusifolium or from other sources for the management of wound healing.

The Preventive Effect on Ethanol-Induced Gastric Lesions of the Medicinal Plant Plumeria rubra: Involvement of the Latex Proteins in the NO/cGMP/K ATP Signaling Pathway.

Plumeria rubra (Apocynaceae) is frequently used in folk medicine for the treatment of gastrointestinal disorders, hepatitis, and tracheitis, among other infirmities. The aim of this study was to investigate the gastroprotective potential of a protein fraction isolated from the latex of Plumeria rubra (PrLP) against ethanol-induced gastric lesions and describe the underlying mechanisms. In a dose-dependent manner, the pretreatment with PrLP prevented ethanol-induced gastric lesions in mice after single intravenous administration. The gastroprotective mechanism of PrLP was associated with the involvement of prostaglandins and balance of oxidant/antioxidant factors. Secondarily, the NO/cGMP/KATP pathway and activation of capsaicin-sensitive primary afferents were also demonstrated as part of the mechanism. This study shows that proteins extracted from the latex of P. rubra prevent gastric lesions induced in experimental animals. Also, the results support the use of the plant in folk medicine.