Evidence of SARS-CoV-2 infection in postmortem lung, kidney, and liver samples, revealing cellular targets involved in COVID-19 pathogenesis

There is an urgent need to understand severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-host interactions involved in virus spread and pathogenesis, which might contribute to the identification of new therapeutic targets. In this study, we investigated the presence of SARS-CoV-2 in postmortem lung, kidney, and liver samples of patients who died with coronavirus disease (COVID-19) and its relationship with host factors involved in virus spread and pathogenesis, using microscopy-based methods. The cases analyzed showed advanced stages of diffuse acute alveolar damage and fibrosis. We identified the SARS-CoV-2 nucleocapsid (NC) in a variety of cells, colocalizing with mitochondrial proteins, lipid droplets (LDs), and key host proteins that have been implicated in inflammation, tissue repair, and the SARS-CoV-2 life cycle (vimentin, NLRP3, fibronectin, LC3B, DDX3X, and PPARγ), pointing to vimentin and LDs as platforms involved not only in the viral life cycle but also in inflammation and pathogenesis. SARS-CoV-2 isolated from a patient´s nasal swab was grown in cell culture and used to infect hamsters. Target cells identified in human tissue samples included lung epithelial and endothelial cells; lipogenic fibroblast-like cells (FLCs) showing features of lipofibroblasts such as activated PPARγ signaling and LDs; lung FLCs expressing fibronectin and vimentin and macrophages, both with evidence of NLRP3- and IL1β-induced responses; regulatory cells expressing immune-checkpoint proteins involved in lung repair responses and contributing to inflammatory responses in the lung; CD34⁺ liver endothelial cells and hepatocytes expressing vimentin; renal interstitial cells; and the juxtaglomerular apparatus. This suggests that SARS-CoV-2 may directly interfere with critical lung, renal, and liver functions involved in COVID-19-pathogenesis.

Preliminary safety assessment of CIGB-210, an investigational peptide for HIV infection

Current human immunodeficiency virus treatments need to be periodically administered lifelong. In this study we assess the effect of repeated doses of an anti-HIV peptide drug candidate in C57BL6 strain. Two schemes of up to 15 administrations and one of 30, daily dosing for 5 days per week, all by the subcutaneous route were evaluated. Different dose concentrations of the peptide were assayed. CIGB-210 treated animals showed no symptoms or abnormal behavior as compared with placebo. All the animals gained weight during the study. Macroscopic evaluation showed no alterations in any of the organs studied. Microscopic analysis of the tissues did not show morphological changes in thymus, stomach, small and large intestines, kidney, brain, or cerebellum. The proliferative response of splenocytes and their capacity to secrete gamma interferon were not compromised by the repeated administration of CIGB-210. There were not statistically significant differences for any of the parameters evaluated during the study among treated and non-treated groups. We can conclude that CIGB-210 is well tolerated in C57BL6 mice in the dose concentration range explored and merits subsequent toxicological studies.

A competitive ELISA for the quantitative determination of the novel anti-HIV drug candidate CIGB-210 in biological fluids

The synthetic peptide CIGB-210 is a promising anti-HIV drug candidate shown to inhibit HIV replication in MT4 cells at the nanomolar range by triggering the rearrangement of vimentin intermediate filaments. Sensitive and specific analytical methods are required for pharmacological studies of CIBG-210 in animals. In this study, we describe the development of a competitive ELISA for the quantitative determination of CIGB-210 using an anti-CIGB-210 hyperimmune serum. After optimization of all the steps, the assay exhibited a dynamic range from 11.87 to 0.0095 µg/mL. The intra-assay coefficient of variation (CV) was lower than or close to 5% for all the six concentrations of the calibrator, and the inter-assay CV was below 10% in five out of the six concentrations tested. No interference of either murine or human plasma was observed. The analyte was stable in plasma after five freeze-thaw cycles, while the hyperimmune serum maintained its binding capacity after 10 freeze-thaw cycles. Furthermore, the ELISA was able to detect the two main metabolites of CIGB-210, although with a tenfold decrease in sensitivity. Our results demonstrate the utility and feasibility of this analytical method for pharmacological experiments in animals as humans.

Non-induced leukocyte extract reduces HIV replication and TNF secretion

According to UNAIDS, the global HIV/AIDS epidemic increased to 40 million the number of people living with the virus around the world. Dialyzable leukocyte extract obtained by our group is a low molecular weight dialyzable material from peripheral human leukocytes previously in vitro induced with Sendai virus (DLE-ind), and more recently, from non-induced leukocytes (DLE n/i). Previous results have shown the ability of DLE-ind to inhibit HIV in vitro replication in MT4 cell; to reduce TNFalpha secretion, and to delay in vivo progression to AIDS in early stage of HIV infection. In this work we present evidences that DLE n/i also inhibits HIV in vitro replication and reduces TNFalpha secretion in human whole blood like DLE obtained from induced leukocytes. Taking together these results show that both properties of DLE, HIV in vitro inhibition and TNF production modulation, are not dependent on in vitro Sendai virus induction of leukocytes.

TNFalpha production in whole blood cultures from healthy individuals

Tumor necrosis factor alpha (TNFalpha) is a major mediator of inflammatory responses and also plays a prominent role in bridging the innate and adaptive phases of immunity. In the present work we attempted to study TNFalpha production in endotoxin-stimulated blood of healthy individuals, and the inter-individual variability in TNFalpha production. For this study, we used diluted whole blood stimulated with lipopolysaccharide (LPS). The levels of the pro-inflammatory cytokine TNFalpha were measured by ELISA and by the L929 cytotoxicity bioassay in 16 and 18 healthy donors, respectively. There were highly significant inter-individual variations in the induced TNFalpha production. It is worth noting that there was no difference in sensitivity between ELISA and the cytotoxicity L929 bioassay. We concluded that whole blood culture is a sensitive method to determine the pro-inflammatory cytokine production in response to endotoxin stimuli in a relevant physiologic milieu. Our data indicate that this method provides appropriate information about the state of cellular immunity of the individual.

Dialyzable leukocyte extract suppresses the activity of essential transcription factors for HIV-1 gene expression in unstimulated MT-4 cells

The human immunodeficiency virus type 1 (HIV-1) contains regulatory regions in its long terminal repeat (LTR) implicated in the control of viral gene expression. We previously demonstrated that Dialyzable Leukocyte Extract (DLE), a preparation derived from immune leukocytes, is able to inhibit HIV-1 replication in MT-4 cell cultures. Here, we examined the effect of DLE on the activation of NF-kappaB and Sp1 transcription factors. NF-kappaB activity was completely suppressed after seven days of treatment with 2.5 U/mL of DLE, with a parallel large reduction in the amounts of Sp1 complexes. These findings correlate with the maximum inhibitory effect on HIV-1 replication described in a previous report. IkappaBalpha and NF-kappaB p65(RelA) gene expression are not regulated by DLE in MT-4 cells. Although up to day, the precise molecular mechanism of DLE biological activity in HIV-1 infection remains unclear, this report presents data that indicate a potential downregulatory effect of DLE on HIV-1 gene expression.

Alcohol consumption and gastric cancer in Mexico

This paper presents an assessment of alcohol consumption, including the popular Mexican liquor tequila, in relation to the incidence of gastric cancer. We conducted a population-based case-control study in Mexico City, with 220 gastric cancer cases and 752 population-based controls. A food frequency questionnaire was used to measure consumption of alcohol and other dietary items. Grams of ethanol were estimated by the Food Intake Analysis System 3.0 software. After adjustment for known risk factors, wine consumption was positively associated with the risk of developing gastric cancer (OR=2.93; CI 95% 1.27-6.75) in the highest category of wine consumption, corresponding to at least 10 glasses of wine per month, with a significant trend (p=0.005). This association remained among intestinal (OR=2.16; CI 95% 0.68-6.92, p-value for trend=0.031 ) and diffuse (OR=4.48; CI 95% 1.44-13.94, p-value for trend=0.018 ) gastric cancer cases. A borderline significant trend between GC risk and total ethanol intake was observed (p=0.068). Consumption of beer and distilled alcoholic beverages including brandy, rum, and tequila was not associated with GC risk. The results indicate the need to focus on the study of the potential effects of different types of wine, with emphasis on components other than ethanol regarding the incidence of gastric cancer, even among populations with moderate to low levels of alcohol consumption.