Variant rs4986790 of toll-like receptor 4 affects the signaling and induces cell dysfunction in patients with severe COVID-19.

OBJECTIVES: We investigated the expression of toll-like receptor (TLR)-4 on the cell surface of innate and adaptive cells from patients with COVID-19 carrying the rs4986790 GG genotype in the TLR4 gene and the functional profile of these cells. METHODS: We included 1169 hospitalized patients with COVID-19. The rs4986790 in TLR4 was identified by real-time polymerase chain reaction. Peripheral blood mononuclear cells were isolated and cultured to evaluate TLR-4 expression on immune cells. Supernatants recovered culture assays were stored, and we measured cytokines and cytotoxic molecules. RESULTS: We showed that the rs4986790 (GG) was significantly associated (P = 0.0310) with severe COVID-19. Cells of patients with COVID-19 carrying the GG genotype have increased the frequency of monocytes and activated naïve and non-switched B cells positive to TLR-4 when cells are stimulated with lipopolysaccharide and with spike protein of SARS-CoV-2. Also, cells from patients with GG COVID-19 cannot produce pro-inflammatory cytokines after lipopolysaccharide stimulus, but they are high producers of cytotoxic molecules at baseline. CONCLUSIONS: The rs4986790 GG genotype of the TLR4 is associated with the risk of COVID-19 and acute respiratory distress syndrome. Peripheral blood mononuclear cells of patients carrying the rs4986790 (TLR4) GG genotype had a limited delivery of pro-inflammatory cytokines compared to the AA and AG genotypes in which TLR-4 stimulation induces IL-10, IL-6, tumor necrosis factor-α, and Fas ligand production.

IFNAR2 relevance in the clinical outcome of individuals with severe COVID-19.

Interferons (IFNs) are a group of cytokines with antiviral, antiproliferative, antiangiogenic, and immunomodulatory activities. Type I IFNs amplify and propagate the antiviral response by interacting with their receptors, IFNAR1 and IFNAR2. In COVID-19, the IFNAR2 (interferon alpha and beta receptor subunit 2) gene has been associated with the severity of the disease, but the soluble receptor (sIFNAR2) levels have not been investigated. We aimed to evaluate the association of IFNAR2 variants (rs2236757, rs1051393, rs3153, rs2834158, and rs2229207) with COVID-19 mortality and to assess if there was a relation between the genetic variants and/or the clinical outcome, with the levels of sIFNAR2 in plasma samples from hospitalized individuals with severe COVID-19. We included 1,202 subjects with severe COVID-19. The genetic variants were determined by employing Taqman® assays. The levels of sIFNAR2 were determined with ELISA in plasma samples from a subgroup of 351 individuals. The rs2236757, rs3153, rs1051393, and rs2834158 variants were associated with mortality risk among patients with severe COVID-19. Higher levels of sIFNAR2 were observed in survivors of COVID-19 compared to the group of non-survivors, which was not related to the studied IFNAR2 genetic variants. IFNAR2, both gene, and soluble protein, are relevant in the clinical outcome of patients hospitalized with severe COVID-19.

COVID-19 Survivor Patients Carrying the Rs35705950 Risk Allele in MUC5B Have Higher Plasma Levels of Mucin 5B.

BACKGROUND: Genetic susceptibility to infectious diseases is partly due to the variation in the human genome, and COVID-19 is not the exception. This study aimed to identify whether risk alleles of known genes linked with emphysema (SERPINA1) and pulmonary fibrosis (MUC5B) are associated with severe COVID-19, and whether plasma mucin 5B differs according to patients' outcomes. MATERIALS AND METHODS: We included 1258 Mexican subjects diagnosed with COVID-19. We genotyped rs2892474 and rs17580 of the SERPINA1 gene and rs35705950 of MUC5B. Based on the rs35705950 genotypes, mucin 5B plasma protein levels were quantified. RESULTS: Homozygous for the risk alleles of the three polymorphisms were found in less than 5% of the study population, but no statistically significant difference in the genotype or allele association analysis. At the protein level, non-survivors carrying one or two copies of the risk allele rs35705950 in MUC5B (GT + TT) had lower levels of mucin 5B compared to the survivors (0.0 vs. 0.17 ng/mL, p = 0.0013). CONCLUSION: The polymorphisms rs28929474 and rs17580 of SERPINA1 and rs35705950 of MUC5B are not associated with the risk of severe COVID-19 in the Mexican population. COVID-19 survivor patients bearing one or two copies of the rs35705950 risk allele have higher plasma levels of mucin 5B.

Los tratamientos populares y el personal de salud: relevancia de la herbolaria / The popular treatments and personal health: importance of herbal

En el campo de la salud, la herbolaria, o plantas utilizadas como medicamentos, representan el principal recurso terapeútico de la medicina indígena, que por los general es menospreciada por los profesores de la medicina alópata.

Pharmacodynamic interaction of the sedative effects of Ternstroemia pringlei (Rose) Standl. with six central nervous system depressant drugs in mice.

ETHNOPHARMACOLOGICAL RELEVANCE: The decoction of dried fruits of Ternstroemia pringlei (Rose) Standl. (Theaceae), commonly known as "Flor de Tila", is used in the Mexican traditional medicine to diminish insomnia and fear. AIM OF THE STUDY: To examine the sedative effects of the dried fruits of Ternstroemia pringlei and investigate a possible synergistic pharmacodynamic interaction between the sedative effect of aqueous extract of this plant and six central nervous system (CNS) depressant drugs. MATERIALS AND METHODS: The sedative effect was performed using the exploratory cylinder test in ICR mice. The extracts and drugs were intraperitoneally administered 30 min before testing in different doses, with exception of ethanol and buspirone which were administered 5 and 20 min before testing, respectively. An isobolographic analysis was used to characterize the interaction between Ternstroemia pringlei extract and six CNS depressant drugs. RESULTS: The intraperitoneal administration of the hexane, dichloromethane, methanol and aqueous extracts of Ternstroemia pringlei showed a dose-dependent sedative effect. Ternstroemia pringlei aqueous extract combined with buspirone, diazepam, diphenhydramine, haloperidol or pentobarbital exerted a super-additive (synergistic) sedative interaction. Whereas the combination Ternstroemia pringlei extract plus ethanol resulted in a sub-additive (attenuate) sedative interaction. CONCLUSIONS: These findings are in agreement with the traditional use of Ternstroemia pringlei in the treatment of insomnia, however it is a plant that interacts in a complex form with CNS depressant drugs. It may represent an advertence on the use of this plant concomitantly with other neuroactive drugs.

[Larrea tridentata. Effect on a non-metabolic model of urolithiasis in rats]. / Larrea tridentata en urofitiasls. Efecto en un modelo no metabólico en ratas.

OBJECTIVE: To evaluate the effect of L. tridentata infusion on the development of urinary calculi in a non-metabolic model. METHODS: Male Wistar rats were divided into two groups (n = 10 each). The experimental group received 1 mL of oral L. tridentata infusion three times daily for 95 days. Control group received 1 mL tap water. Five days after initiating treatment, urolithiasis was induced inserting a series of 15 knots of 5-0 chromic catgut into the urinary bladder. Measurements included body weight and water intake, complete blood counts, glucose, BUN, creatinine, bacterial culture, and weight of urinary stones and sands. RESULTS: No statistically significant differences were found between groups for any variable. CONCLUSIONS: An infusion of L. tridentata was not effective in the prevention of urolith formation in the suture-induced rat model. It produced no alterations in body weight gain, blood counts, or water intake. Future work is needed to completely rule out any effect of the plant on urolith formation.

Mechanisms of relaxant action of a crude hexane extract of Gnaphalium liebmannii in guinea pig tracheal smooth muscle.

We investigated the mechanisms of action of Gnaphalium liebmannii which is used as a folk medicine in México for treating various respiratory diseases such as gripe, fever, asthma, cough, cold, bronchitis, expectorating, and bronchial affections. The tension changes of guinea pig tracheal segments were isometrically recorder on a polygraph. Hexane extract of Gnaphalium liebmannii was the most active relaxant extract (IC(30)=54.23+/-19.79 microg/mL with 99.5+/-3.2 % of relaxation), followed by dichloromethane extract (IC(30)=120.22+/-5.27 microg/mL) and methanol extract (IC(30)=190.25+/-30.02 microg/mL). Hexane extract produced a parallel rightward shift of the concentration-response curve of carbachol in a competitive manner (pA(2)=-2.4), but did not modify the concentration-response curves for histamine. The relaxant effect of hexane extract of Gnaphalium liebmannii was unaffected by the presence of propranolol (3x10(-6)M) or glibenclamide (10 microM). However hexane extract produced a leftward shifts of the concentration-response curve of forskolin (10(-8) to 10(-3)M), nitroprusside (10(-10) to 10(-6)M), isoproterenol (3x10(-10) to 3x10(-5)M) and aminophylline (10(-11) to 10(-2)M). The above results suggest that Gnaphalium liebmannii induce relaxation of the tracheal muscle, probably via phosphodiesterase inhibition. The bronchodilator effect of Gnaphalium liebmannii might explain in part their traditional use as anti-asthmatic remedy.

In vitro susceptibility of Entamoeba histolytica and Giardia lamblia to plants used in Mexican traditional medicine for the treatment of gastrointestinal disorders.

In our search for new antiprotozoal chemotherapy, we collected a selection of 26 plants used in Mexican traditional medicine for the treatment of gastrointestinal disorders. Methanolic extracts of these species were screened for their antiprotozoal activity against Entamoeba histolytica and Giardia lamblia trophozoites using in vitro tests. Among the tested extracts, the derivates of following species showed selectivity and significant antiprotozoal activity: Chiranthodendron pentadactylon, Annona cherimola and Punica granatum were the most active on Entamoeba histolytica with IC50 < 30 microg/ml. Dorstenia contrajerva, Senna villosa and Ruta chalepensis were the most active toward Giardia lamblia with IC50 < 38 microg/ml. The potency of Chiranthodendron pentadactylon (IC50 2.5 microg/ml) on Entamoeba histolytica was close that of to emetine, but far less than metronidazole, drugs used as control. The results of the antiprotozoal screening support the popular uses of the studied species for the treatment of diarrhoea and dysentery in Mexican traditional medicine.

Effect of Gnaphalium conoideum HBK on guinea pig airway smooth muscle: role of L-type Ca2+ channels.

Plants from the Gnaphalium genus have been used in the Mexican traditional medicine for digestive and respiratory complaints. In the present study, the effect of methanolic extract from Gnaphalium conoideum HBK on the responses to contractile agonists was assessed in guinea pig tracheas, and the possible role of L-type Ca2+ channels was explored in tracheal guinea pig isolated myocytes. Cumulative concentration-response curves to carbachol or histamine, as well as contractile responses to 60 mM KCl were evaluated with or without 30 min preincubation with 20 or 100 microg ml(-1) Gnaphalium conoideum. Likewise, intracellular Ca2+ concentrations were measured by microfluorometric method (fura-2 AM) in isolated tracheal myocytes with or without preincubation with 0.1, 0.31 or 1 microg ml(-1)Gnaphalium conoideum. We found that methanolic extract from Gnaphalium conoideum significantly diminished the contractile responses to histamine, but not to carbachol or KCl. In isolated myocytes, Gnaphalium conoideum significantly reduced the intracellular Ca2+ rise induced by 60 mM KCl. Because histamine contractile responses are largely dependent on extracellular Ca2+, and KCl responses are mainly mediated through L-type Ca2+ channels, our results suggested that methanolic extract from Gnaphalium conoideum might be acting as a partial blocker of these Ca2+ channels.

Antibacterial activity of crude extracts from Mexican medicinal plants and purified coumarins and xanthones.

Thirty-two extracts from 22 Mexican medicinal plants of 15 different families were assayed to determine their antibacterial activity against Escherichia coli and Staphylococcus aureus. Seventeen plants showed antibacterial activity, while five plants showed no activity against both bacteria. All of the extracts showed higher activity against Staphylococcus aureus (methicillin-sensitive and methicillin-resistant) than against Escherichia coli, except one. Among the plants examined, Bursera simaruba (L.) Sarg. (Burseraceae), Haematoxylum brasiletto H. Karst. (Fabaceae), Calophyllum brasiliense Cambess. (Clusiaceae), and Mammea americana L. (Clusiaceae) were highly active against Staphylococcus aureus. Coumarins (mammea A/BA and mammea A/AA) and xanthones, namely jacareubin and 1,3,5,6-tetrahydroxy-2-(3,3-dimethylallyl) xanthone, were isolated as the principle compounds from the last two plants.

Trypanocidal constituents in plants 1. Evaluation of some Mexican plants for their trypanocidal activity and active constituents in Guaco, roots of Aristolochia taliscana.

Crude extracts of Mexican medicinal plants were screened for trypanocidal activity against Trypanosoma cruzi, which is the etiological agent for Chagas' disease, one of the most serious protozoan diseases in Latin America. There were 43 kinds of methanolic and other organic extracts from 39 plants which were examined by the preliminary screening test to see immobilization of epimastigotes of T. cruzi in vitro. Eighteen of them showed activity at the concentration of 2 mg/ml after incubation for 2 h, while 13 showed activity at the concentration of 1 mg/ml after incubation for 48 h. Among them, the MeOH extract of roots of Aristolochia taliscana (Aristolochiaceae), locally known as "Guaco," immobilized all the epimastigotes even at lower concentration of 0.5 mg/ml (48 h). In order to identify principal compounds for this activity, the MeOH extract of Guaco was subjected to bioassay-guided fractionation. From the active fractions, four neolignans, eupomatenoid-7 (1), licarin A (2), eupomatenoid-1 (5) and licarin B (6), and two lignans, austrobailignan-7 (3) and fragransin E1 (4) were isolated. Compounds 1-4 immobilized all the epimastigotes at the minimum concentration of 25-75 microg/ml after incubation for 48 h, while compounds 5 and 6 were inactive. Corresponding concentration of gossypol, berberine chloride and harmine was 280 microg/ml, 300 microg/ml and >500 microg/ml, respectively.

Leaf extracts of Carlowrightia cordifolia induce macrophage nitric oxide production.

Carlowrightia cordifolia (Acanthaceae) is a medicinal plant used in northeastern Mexico as a traditional remedy against inflammation. As tissue release of nitric oxide (NO) has been correlated with both inflammatory and anti-inflammatory processes, the aim of this study was to determine the effect of C. cordifolia leaf extracts on macrophage NO production. Lipopolysaccharide (LPS)-stimulated and non-LPS-stimulated mouse peritoneal macrophages were incubated with aqueous, ethanol, methanol and hexane extracts of C. cordifolia leaves. All extracts inhibited NO release from LPS-stimulated macrophages, with methanol and hexane extracts showing the greatest inhibition. On the other hand, macrophage cultures treated with extracts without LPS-stimulation produced high releases of NO. These unexpected results suggest two different ways by which leaf extracts may act, depending on cell status. On the other hand, data on NO activity in relation to inflammatory/anti-inflammatory auto-regulatory feedback and high concentrations of NO release by non-stimulated macrophages agreed with the hypothesis that NO may have an inhibitory effect in vascular inflammation.