Emergence and Spread of a B.1.1.28-Derived P.6 Lineage with Q675H and Q677H Spike Mutations in Uruguay

Uruguay controlled the viral dissemination during the first nine months of the SARS-CoV-2 pandemic. Unfortunately, towards the end of 2020, the number of daily new cases exponentially increased. Herein, we analyzed the country-wide genetic diversity of SARS-CoV-2 between November 2020 and April 2021. We identified that the most prevalent viral variant during the first epidemic wave in Uruguay (December 2020-February 2021) was a B.1.1.28 sublineage carrying Spike mutations Q675H + Q677H, now designated as P.6, followed by lineages P.2 and P.7. P.6 probably arose around November 2020, in Montevideo, Uruguay's capital department, and rapidly spread to other departments, with evidence of further local transmission clusters; it also spread sporadically to the USA and Spain. The more efficient dissemination of lineage P.6 with respect to P.2 and P.7 and the presence of mutations (Q675H and Q677H) in the proximity of the key cleavage site at the S1/S2 boundary suggest that P.6 may be more transmissible than other lineages co-circulating in Uruguay. Although P.6 was replaced by the variant of concern (VOC) P.1 as the predominant lineage in Uruguay since April 2021, the monitoring of the concurrent emergence of Q675H + Q677H in VOCs should be of worldwide interest.

Real-Time Genomic Surveillance for SARS-CoV-2 Variants of Concern, Uruguay

We developed a genomic surveillance program for real-time monitoring of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants of concern (VOCs) in Uruguay. We report on a PCR method for SARS-CoV-2 VOCs, the surveillance workflow, and multiple independent introductions and community transmission of the SARS-CoV-2 P.1 VOC in Uruguay.

AB0193 PRESENCE OF SUBLINICAL SYNOVITIS IN A ESTABLISHED RHEUMATOID ARTHRITIS COHORT

Background:

Some studies prove that a significant percentage of patients with rheumatoid arthritis (RA) in sustained clinical remission has radiological progression or joint damage, and the presence of residual activity objectified by imaging studies such as ultrasonography could be related to a relapse or flare of RA.(1,2)

Objectives:

To determine the presence of subclinical synovitis measured by ultrasonography in patients with RA on sustained clinical remission from the Rheumatology service at Hospital de Clínicas, San Lorenzo, Paraguay.

Materials and Methods:

Prospective, cross sectional, descriptive study, in RA patients meeting ACR/EULAR 2010 criteria, older than 18 years, on sustained clinical remission (≥6 months), measured by ESR-DAS28 (<2,6), doing follow-ups on our service. A healthy control group was included. All groups signed informed consent. Synovial hypertrophy (SH) and intraarticular vascularization grades on Power Doppler (PD) mode were determined according to EULAR recommendations and OMERACT 7 group definitions. Clinical data were obtained from the service’s registries.

SPSS 23rd version was used for data analysis. Quantitative variables were presented as means and qualitative as frequencies. Chi square test was performed for comparisons between dichotomous variables and t Student for continuous. For comparisons between variables the Spearman’s rank correlation coefficient was performed, and p≤0.05 for statistical significance. Factors predicting subclinical synovitis were analyzed with Odds Ratio (OR) CI 95%.

Results:

From 147 patients, 31 (21%) met remission criteria; 87.1% women, mean age 51.9±14.8 years. Mean disease duration was 9,06±10,81 years. 64,5% were RF and ACPA positive and 25,9% had erosions.

Ultrasonograms were made in 20 joints of both hands: radiocarpals (RC), metacarpophalangeals (MCP) and proximal interphalangeals (PIP). 12 patients (38.7%) presented subclinical synovitis (SH≥2+PD), more frequently on RC (29% right, 22.6% left), and MCP (9.7% on 2RMCP, 9.7% 4LMCP). These patients had greater CDAI (3.9±1.37 vs 2.89±1.15, p=0.03), HAQ (0.14±0.29 vs 0.00±0.00, p=0.04), CRP (9.90±7.46 vs 4.74±2.30, p=0.00) RF levels (502.67±275.66 vs 200.92±158.43, p=0,00), greater prednisone (16.5% vs 3.2%, p=0.04), and methotrexate use (20.16±5.54 vs 17.50±3.98, p=0.01). None of the healthy controls presented subclinical synovitis.

In binary logistic regression CRP levels, RF titers and methotrexate doses were associated to subclinical synovitis. This association is not found in multivariate logistic regression. Negative association was found between subclinical synovitis and two csDMARDs use.

Conclusion:

This is the first study of its type in Paraguayan patients, which clearly evidenced that an important part of RA patients in clinical remission still presented subclinical synovitis (HS≥2 + PD). It was associated with CRP, RF and methotrexate dose.

References:

[1]Płaza M, Nowakowska-Płaza A, Pracoń G, Sudoł-Szopińska I. Role of ultrasonography in the diagnosis of rheumatic diseases in light of ACR/EULAR guidelines. J Ultrason. marzo de 2016;16(64):55-64.

[2]Foltz V, Gandjbakhch F, Etchepare F, Rosenberg C, Tanguy ML, Rozenberg S, et al. Power Doppler ultrasound, but not low-field magnetic resonance imaging, predicts relapse and radiographic disease progression in rheumatoid arthritis patients with low levels of disease activity. Arthritis & Rheumatism. 2012;64(1):67-76.

Disclosure of Interests:

None declared

Effects of microcystins over short- and long-term memory and oxidative stress generation in hippocampus of rats

Microcystins produced by cyanobacteria are potent inhibitors of some protein phosphatases, but recent evidence also indicates its potential to generate oxidative stress. In the present study, the effects of microcystin raw extracts (Mic; 0.01 and 20microg/L) and purified okadaic acid (OA; 0.01 and 10microg/L) on short- and long-term memory alteration and antioxidant and oxidative damage were investigated in hippocampus of rats. The results showed an amnesic effect with 0.01 and 20microg/L Mic on retrieval and only with 0.01microg/L Mic on spatial learning. Parallel to these effects oxidative damage was observed as evidenced by augmented levels of lipid peroxides and DNA damage and the absence of antioxidant responses in terms of total oxyradical scavenging capacity. Phase II reactions catalyzed by glutathione-S-transferase were not modified after microcystins exposure. Overall this study showed physiological events (retrieval and spatial learning) that can be related to the classical toxic effects of microcystins (i.e., phosphatase inhibition). In addition, evidence of alternative toxicity mechanisms via oxidative stress generation was also obtained. The fact that organic anion transporter polypeptides (OATP) involved in microcystins uptake are expressed not only in liver but also in brain points to the environmental relevance of the observed effects.