Dynamics of hemoglobins during nodule development, nitrate response, and dark stress in Lotus japonicus.

Legume nodules express multiple leghemoglobins (Lbs) and non-symbiotic hemoglobins (Glbs), but how they are regulated is unclear. Here, we study the regulation of all Lbs and Glbs of Lotus japonicus in different physiologically relevant conditions and mutant backgrounds. We quantified hemoglobin expression, localized reactive oxygen species (ROS) and nitric oxide (NO) in nodules, and deployed mutants deficient in Lbs and in the transcription factors NLP4 (associated with nitrate sensitivity) and NAC094 (associated with senescence). Expression of Lbs and class 2 Glbs was suppressed by nitrate, whereas expression of class 1 and 3 Glbs was positively correlated with external nitrate concentrations. Nitrate-responsive elements were found in the promoters of several hemoglobin genes. Mutant nodules without Lbs showed accumulation of ROS and NO and alterations of antioxidants and senescence markers. NO accumulation occurred by a nitrate-independent pathway, probably due to the virtual disappearance of Glb1-1 and the deficiency of Lbs. We conclude that hemoglobins are regulated in a gene-specific manner during nodule development and in response to nitrate and dark stress. Mutant analyses reveal that nodules lacking Lbs experience nitro-oxidative stress and that there is compensation of expression between Lb1 and Lb2. They also show modulation of hemoglobin expression by NLP4 and NAC094.

Different Cis-Regulatory Elements Control the Tissue-Specific Contribution of Plastid ω-3 Desaturases to Wounding and Hormone Responses.

Trienoic fatty acids are essential constituents of biomembranes and precursors of jasmonates involved in plant defense responses. Two ω-3 desaturases, AtFAD7 and AtFAD8, synthetize trienoic fatty acids in the plastid. Promoter:GUS and mutagenesis analysis was used to identify cis-elements controlling AtFAD7 and AtFAD8 basal expression and their response to hormones or wounding. AtFAD7 promoter GUS activity was much higher than that of AtFAD8 in leaves, with specific AtFAD7 expression in the flower stamen and pistil and root meristem and vasculature. This specific tissue and organ expression of AtFAD7 was controlled by different cis-elements. Thus, promoter deletion and mutagenesis analysis indicated that WRKY proteins might be essential for basal expression of AtFAD7 in leaves. Two MYB target sequences present in the AtFAD7 promoter might be responsible for its expression in the flower stamen and stigma of the pistil and in the root meristem, and for the AtFAD7 wound-specific response. Two MYB target sequences detected in the distal region of the AtFAD8 gene promoter seemed to negatively control AtFAD8 expression, particularly in true leaves and flowers, suggesting that MYB transcription factors act as repressors of AtFAD8 gene basal expression, modulating the different relative abundance of both plastid ω-3 desaturases at the transcriptional level. Our data showed that the two ABA repression sequences detected in the AtFAD7 promoter were functional, suggesting an ABA-dependent mechanism involved in the different regulation of both ω-3 plastid desaturases. These results reveal the implication of different signaling pathways for the concerted regulation of trienoic fatty acid content in Arabidopsis.

Three classes of hemoglobins are required for optimal vegetative and reproductive growth of Lotus japonicus: genetic and biochemical characterization of LjGlb2-1.

Legumes express two major types of hemoglobins, namely symbiotic (leghemoglobins) and non-symbiotic (phytoglobins), with the latter being categorized into three classes according to phylogeny and biochemistry. Using knockout mutants, we show that all three phytoglobin classes are required for optimal vegetative and reproductive development of Lotus japonicus. The mutants of two class 1 phytoglobins showed different phenotypes: Ljglb1-1 plants were smaller and had relatively more pods, whereas Ljglb1-2 plants had no distinctive vegetative phenotype and produced relatively fewer pods. Non-nodulated plants lacking LjGlb2-1 showed delayed growth and alterations in the leaf metabolome linked to amino acid processing, fermentative and respiratory pathways, and hormonal balance. The leaves of mutant plants accumulated salicylic acid and contained relatively less methyl jasmonic acid, suggesting crosstalk between LjGlb2-1 and the signaling pathways of both hormones. Based on the expression of LjGlb2-1 in leaves, the alterations of flowering and fruiting of nodulated Ljglb2-1 plants, the developmental and biochemical phenotypes of the mutant fed on ammonium nitrate, and the heme coordination and reactivity of the protein toward nitric oxide, we conclude that LjGlb2-1 is not a leghemoglobin but an unusual class 2 phytoglobin. For comparison, we have also characterized a close relative of LjGlb2-1 in Medicago truncatula, MtLb3, and conclude that this is an atypical leghemoglobin.

Telmisartan for treatment of Covid-19 patients: An open multicenter randomized clinical trial.

Background: Angiotensin receptor blockers (ARBs), such as telmisartan, have been postulated to treat Covid-19-induced lung inflammation. Methods: This is a parallel-group, randomized, two-arm, open-label, adaptive, multicenter superiority trial with 1:1 allocation ratio. Participants included patients from 18 years of age hospitalized with Covid-19 with 4 or fewer days since symptom onset enrolled at a university and a community hospital in Buenos Aires, Argentina. Exclusion criteria included prior intensive care unit (ICU) admission and use of ARBs/angiotensin converting enzyme inhibitors at randomization. Control arm received standard care alone and treatment arm telmisartan 80 mg twice daily for 14 days. Primary outcomes were C-reactive protein (CRP) plasma levels at day 5 and 8 after randomization. Secondary outcomes included time to discharge within 15 days, admission to ICU and death at 15- and 30-days. NCT04355936 (Completed). Findings: A pragmatic decision to end the study before the third interim analysis was made on Oct. 30th due to sharp reduction in recruitment. A total of 162 patients were randomized. 158 patients enrolled between May 14 and October 30 2020, were included in the analysis, 80 in the standard care and 78 in the telmisartan added to standard care group. Baseline absolute CRP serum levels were 5.53 ± 6.19 mg/dL (95% CI 6.91 to 4.15, n = 80) and 9.04 ± 7.69 (95% CI 9.04 to 10.82, n = 74) in the standard care and telmisartan added to standard care groups, respectively. Day 5 control-group CRP levels were 6.06 ± 6.95 mg/dL (95% CI 7.79-4.35, n = 66) while telmisartan group were 3.83 ± 5.08 mg/dL (95% CI 5.08-2.59, n = 66, p = 0.038). Day 8 CRP levels were 6.30 ± 8.19 mg/dL (95% CI 8.79-3.81, n = 44) and 2.37 ± 3.47 mg/dL (95% CI 3.44-1.30, n = 43, p = 0.0098) in the control and telmisartan groups, respectively (all values expressed as mean ± SD). Kaplan-Meier analysis showed that telmisartan-treated patients had a lower median time-to-discharge (control=15 days; telmisartan=9 days). Death by day 30 was reduced in the telmisartan-treated group (control 22.54%, 16/71; telmisartan 4.29%, 3/70 participants; p = 0.0023). Composite ICU, mechanical ventilation or death was reduced by telmisartan treatment at days 15 and 30. No adverse events were reported. Interpretation: Our study suggests that the ARB telmisartan, a widely used antihypertensive drug, is safe and could reduce morbidity and mortality in hospitalized patients infected with SARS -CoV-2 by anti-inflammatory effects. Further studies employing telmisartan are needed for confirmation of our results and to define its true therapeutic value as a tool against Covid-19.

A Plant Gene Encoding One-Heme and Two-Heme Hemoglobins With Extreme Reactivities Toward Diatomic Gases and Nitrite.

In plants, symbiotic hemoglobins act as carriers and buffers of O2 in nodules, whereas nonsymbiotic hemoglobins or phytoglobins (Glbs) are ubiquitous in tissues and may perform multiple, but still poorly defined, functions related to O2 and/or nitric oxide (NO). Here, we have identified a Glb gene of the model legume Medicago truncatula with unique properties. The gene, designated MtGlb1-2, generates four alternative splice forms encoding Glbs with one or two heme domains and 215-351 amino acid residues. This is more than double the size of any hemoglobin from plants or other organisms described so far. A combination of molecular, cellular, biochemical, and biophysical methods was used to characterize these novel proteins. RNA-sequencing showed that the four splice variants are expressed in plant tissues. MtGlb1-2 is transcriptionally activated by hypoxia and its expression is further enhanced by an NO source. The gene is preferentially expressed in the meristems and vascular bundles of roots and nodules. Two of the proteins, bearing one or two hemes, were characterized using mutants in the distal histidines of the hemes. The Glbs are extremely reactive toward the physiological ligands O2, NO, and nitrite. They show very high O2 affinities, NO dioxygenase activity (in the presence of O2), and nitrite reductase (NiR) activity (in the absence of O2) compared with the hemoglobins from vertebrates and other plants. We propose that these Glbs act as either NO scavengers or NO producers depending on the O2 tension in the plant tissue, being involved in the fast and fine tuning of NO concentration in the cytosol in response to sudden changes in O2 availability.

Corrigendum: A Plant Gene Encoding One-Heme and Two-Heme Hemoglobins With Extreme Reactivities Toward Diatomic Gases and Nitrite.

[This corrects the article DOI: 10.3389/fpls.2020.600336.].

Phytoglobins in the nuclei, cytoplasm and chloroplasts modulate nitric oxide signaling and interact with abscisic acid.

Symbiotic hemoglobins provide O2 to N2 -fixing bacteria within legume nodules, but the functions of non-symbiotic hemoglobins or phytoglobins (Glbs) are much less defined. Immunolabeling combined with confocal microscopy of the Glbs tagged at the C-terminus with green fluorescent protein was used to determine their subcellular localizations in Arabidopsis and Lotus japonicus. Recombinant proteins were used to examine nitric oxide (NO) scavenging in vitro and transgenic plants to show S-nitrosylation and other in vivo interactions with NO and abscisic acid (ABA) responses. We found that Glbs occur in the nuclei, chloroplasts and amyloplasts of both model plants, and also in the cytoplasm of Arabidopsis cells. The proteins show similar NO dioxygenase activities in vitro, are nitrosylated in Cys residues in vivo, and scavenge NO in the stomatal cells. The Cys/Ser mutation does not affect NO dioxygenase activity, and S-nitrosylation does not significantly consume NO. We demonstrate an interaction between Glbs and ABA on several grounds: Glb1 and Glb2 scavenge NO produced in stomatal guard cells following ABA supply; plants overexpressing Glb1 show higher constitutive expression of the ABA responsive genes Responsive to ABA (RAB18), Responsive to Dehydration (RD29A) and Highly ABA-Induced 2 (HAI2), and are more tolerant to dehydration; and ABA strongly upregulates class 1 Glbs. We conclude that Glbs modulate NO and interact with ABA in crucial physiological processes such as the plant's response to dessication.

Recent advances in environmental and clinical analysis using microring resonator-based sensors.

Progress in the development of biosensors has dramatically improved analytical techniques. Biosensors have advantages over more conventional analytical techniques arising from attributes such as straightforward analyses, higher throughput, miniaturization, smaller sample input, and lower cost. Microring optical resonators have emerged in the area of optical sensors as an exceptional choice due to their sensitivity, ease of fabrication, multiplexity capability and label-free detection. In this paper, the sensing principle of these sensors is described. In addition, we summarize and highlight their most recent and relevant applications in environmental and clinical detection analysis.

Multiplexed microRNA Expression Profiling by Combined Asymmetric PCR and Label-Free Detection using Silicon Photonic Sensor Arrays.

Analysis methods based upon the quantitative, real-time polymerase chain reaction are extremely powerful; however, they face intrinsic limitations in terms of target multiplexing. In contrast, silicon photonic microring resonators represent a modularly multiplexable sensor array technology that is well-suited to the analysis of targeted biomarker panels. In this manuscript we employ an asymmetric polymerase chain reaction approach to selectively amplify copies of cDNAs generated from targeted miRNAs before multiplexed, label-free quantitation through hybridization to microring resonator arrays pre-functionalized with capture sequences. This method, which shows applicability to low input amounts and a large dynamic range, was demonstrated for the simultaneous detection of eight microRNA targets from twenty primary brain tumor samples with expression profiles in good agreement with literature precedent.

Redefining nitric oxide production in legume nodules through complementary insights from electron paramagnetic resonance spectroscopy and specific fluorescent probes.

Nitric oxide (NO) is a signaling molecule with multiple functions in plants. Given its critical importance and reactivity as a gaseous free radical, we have examined NO production in legume nodules using electron paramagnetic resonance (EPR) spectroscopy and the specific fluorescent dye 4,5-diaminofluorescein diacetate. Also, in this context, we critically assess previous and current views of NO production and detection in nodules. EPR of intact nodules revealed that nitrosyl-leghemoglobin (Lb2+NO) was absent from bean or soybean nodules regardless of nitrate supply, but accumulated in soybean nodules treated with nitrate that were defective in nitrite or nitric oxide reductases or that were exposed to ambient temperature. Consequently, bacteroids are a major source of NO, denitrification enzymes are required for NO homeostasis, and Lb2+NO is not responsible for the inhibition of nitrogen fixation by nitrate. Further, we noted that Lb2+NO is artifactually generated in nodule extracts or in intact nodules not analyzed immediately after detachment. The fluorescent probe detected NO formation in bean and soybean nodule infected cells and in soybean nodule parenchyma. The NO signal was slightly decreased by inhibitors of nitrate reductase but not by those of nitric oxide synthase, which could indicate a minor contribution of plant nitrate reductase and supports the existence of nitrate- and arginine-independent pathways for NO production. Together, our data indicate that EPR and fluorometric methods are complementary to draw reliable conclusions about NO production in plants.

Combining asymmetric PCR-based enzymatic amplification with silicon photonic microring resonators for the detection of lncRNAs from low input human RNA samples.

A method for quantifying biologically relevant long-non-coding RNAs by combining nucleic acid amplification via asymmetric polymerase chain reaction (PCR) with label-free PCR product detection using silicon photonic microring resonator arrays is described. This approach eliminates the need for fluorophores, which presents a limit for spectral multiplexing in conventional qPCR methods, and rather offers potential for much higher levels of plexity by spatially arraying capture probes. Here, we demonstrate the potential of this technique to detect two differentially expressed lncRNA transcripts and an internal control mRNA transcript in different commercial human tissue specimens, as well as in a glioblastoma cell line using only nanogram input amounts of total RNA. The obtained results were validated using single-plex RT-qPCR and found to be in good agreement, demonstrating the potential of this technique for lncRNA quantification applications.

Immunologic Response Elicited in Breast Cancer Patients Receiving a NeuGcGM3-based Vaccine as Adjuvant Therapy.

This study aimed to investigate the immunogenicity of a cancer vaccine consisting of the NeuGcGM3 ganglioside combined with the outer membrane protein complex of Neisseria meningitides to form very small size particles. The vaccine is administered together with Montanide ISA51, as adjuvant treatment for breast cancer patients. After surgical resection and standard first-line chemo/radiotherapy, breast cancer patients in stage II-III were enrolled in a phase III clinical trial and allocated into 2 strata, according to the number of positive lymph nodes [stratum I (0-3); stratum II (≥4)]. Subsequently, patients were randomly assigned to receive the vaccine or placebo. The treatment consisted of 5 vaccine doses (200 µg) every 2 weeks and thereafter monthly reimmunizations to complete 15 doses. The vaccine was well-tolerated and high titers of immunoglobulin M and immunoglobulin G anti-NeuGcGM3 antibodies were similarly detected in each stratum. Hyperimmune sera were able to specifically recognize and kill the NeuGcGM3-expressing L1210 tumor cell line, and these functional capacities were significantly associated with a better clinical outcome in patients of stratum II. Besides, postimmune sera had the capacity to revert in vitro the immunosuppression induced by NeuGcGM3, as measured by the prevention of CD4 downmodulation on human T lymphocytes. Vaccination had no impact on the frequency of regulatory T cells or circulating NK cells. This study demonstrated, for the first time, the immunogenicity of the NeuGcGM3/VSSP/Montanide ISA 51 vaccine in the adjuvant setting and describes the functionality of induced anti-NeuGcGM3 antibodies as potential surrogate biomarkers of clinical benefit.

Effect of angiotensin-converting enzyme inhibitors on vascular endothelial function in hypertensive patients after intensive periodontal treatment.

There is a relation between vascular endothelial function, atherosclerotic disease, and inflammation. Deterioration of endothelial function has been observed twenty-four hours after intensive periodontal treatment. This effect may be counteracted by the action of angiotensin-converting enzyme inhibitors, which improve endothelial function. The aim of the present study was to evaluate vascular endothelial function after intensive periodontal treatment, in hypertensive patients treated with angiotensinconverting enzyme inhibitors. A prospective, longitudinal, comparative study involving repeated measurements was conducted. Fifty-two consecutive patients with severe periodontal disease were divided into two groups, one comprising hypertensive patients treated with converting enzyme inhibitors and the other comprising patients with no clinical signs of pathology and not receiving angiotensin-converting enzyme inhibitors. Endothelial function was assessed by measuring postischemic dilation of the humeral artery (baseline echocardiography Doppler), and intensive periodontal treatment was performed 24h later. Endothelial function was re-assessed 24h and 15 days after periodontal treatment. STATISTICAL ANALYSIS: Results were analyzed using the SPSS 20 statistical software package. Student's t test and MANOVA were calculated and linear regression analysis with 95% confidence intervals and α<0.05 was performed. Arterial dilation at 24 hours was lower compared to baseline in both groups; values corresponding to the groups receiving angiotensin-converting enzyme inhibitors were 11.89 ± 4.87 vs. 7.30 ± 2.90% (p<0.01) and those corresponding to the group not receiving ACE inhibitors were 12.72 ± 4.62 vs. 3.56 ± 2.39 (p<0.001). The differences between groups were statistically significant (p<0.001). CONCLUSION: The increase in endothelial dysfunction after intensive periodontal treatment was significantly lower in hypertensive patients treated with angiotensin-converting enzyme inhibitors. Endothelial function improved 15 days after periodontal treatment, reaching baseline values. These results support the protective effect of angiotensin converting enzyme inhibitors on the endothelial function after intensive periodontal treatment.

Existe relación entre la disfunción del endotelio vascular, la enfermedad aterosclerótica y la inflamación. A las 24 h del tratamiento intensivo de la enfermedad periodontal se produce un deterioro de la función endotelial. Este efecto podría ser balanceado por la acción de los inhibidores de la enzima convertidora de la angiotensina que mejoran la función endotelial. El objetivo del presente estudio fue evaluar la función endotelial vascular después del tratamiento periodontal intensivo, en pacientes hipertensos tratados con inhibidores de la enzima convertidora de la angiotensina. Se realizó un estudio prospectivo, longitudinal, comparativo, con mediciones repetidas. Se incorporaron 52 pacientes consecutivos, con enfermedad periodontal severa divididos en dos grupos, uno con hipertensión arterial tratados con inhibidores de la enzima convertidora y el otro sin inhibidores ni patología clínicamente evidente. Se determinó la función endotelial cuantificando la dilatación de la arterial humeral post isquemia ecocardiografía Doppler basal. A las 24 h se efectuó el tratamiento periodontal intensivo; a 24 h y 15 días posteriores se reevaluó la función endotelial. Análisis estadístico: se empleó el paquete estadístico SPSS 20. Se realizaron: t-test de Student, MANOVA y análisis de regresión lineal con intervalos de confianza del 95% y α <0.05. Resultados: a las 24 h post tratamiento periodontal se observó una menor dilatación arterial en ambos grupos en relación a la dilatación arterial basal, siendo para el grupo con inhibidores 11.89 ±4.87 vs. 7.30 ± 2.90%, p<0.01 y para el grupo sin inhibidores 12.72 ± 4.62 vs 3.56 ± 2.39, p<0.001, con diferencias significativas entre ambos p< 0.001. En conclusión el aumento de la disfunción endotelial post tratamiento intensivo periodontal fue significativamente menor en hipertensos que recibieron inhibidores de la enzima convertidora de la angiotensina. La función endotelial mejoró a los 15 días de efectuado el tratamiento, alcanzando los valores inciales. Estos resultados permitirían relacionar a los inhibidores de la enzima convertidora con un efecto protector del endotelio posterior al tratamiento intensivo de la enfermedad periodontal.

Papel de la tiorredoxina-1 en el atontamiento cardíaco en ratones transgénicos / Role of Thioredoxin-1 on Myocardial Stunning in Transgenic Mice

Introducción: La disfunción ventricular posisquémica (miocardio atontado) involucra un aumento del estrés oxidativo. En este sentido, la célula cuenta con mecanismos de defensa, como la tiorredoxina-1, un antioxidante que protege al miocardio de la lesión por isquemia/reperfusión, reduciendo el tamaño del infarto. Objetivo: Evaluar el comportamiento de la función ventricular sistólica y diastólica, particularmente estudiando la rigidez miocárdica y la relajación isovolúmica en el miocardio atontado en diferentes ratones transgénicos. Material y métodos: Se utilizaron corazones de ratones que sobreexpresan tiorredoxina-1 y de ratones transgénicos que sobreexpresan tiorredoxina-1 mutada en su sitio activo (dominante negativo), comparados con los de ratones no transgénicos, los cuales fueron sometidos a 15 minutos de isquemia global y 30 minutos de reperfusión utilizando la técnica de Langendorff. Se evaluó la función ventricular sistólica y diastólica y se calculó el t63 y el t93 como índice de relajación isovolúmica. Resultados: Las mediciones a los 30 minutos de reperfusión mostraron una mejoría significativa del estado contráctil en los ratones tiorredoxina-1 (57,4 ± 4,9 mm Hg; p ≤ 0,05 vs. no transgénicos) y también en la rigidez (11,8 ± 2,9 mm Hg; p ≤ 0,05 vs. no transgénicos). Por otra parte, en los ratones dominantes negativos se observó un aumento de la rigidez (37,7 ± 5,5 mm Hg; p ≤ 0,05 vs. no transgénicos) y un enlentecimiento de la relajación a los 30 minutos de la reperfusión (78,2 ± 9,8 mseg; p ≤ 0,05 vs. no transgénicos). Conclusión: Este trabajo evidencia el rol protector de la tiorredoxina-1 en el miocardio atontado y su importancia fisiopatológica en ratones que sobreexpresan este antioxidante.

Background: Postischemic ventricular dysfunction (myocardial stunning) involves increased oxidative stress. In this sense, the cell has defense mechanisms, as thioredoxin-1, an antioxidant that protects the myocardium from ischemia/reperfusion injury, reducing infarct size. Objective: The aim of this study was to evaluate systolic and diastolic ventricular function, specifically analyzing myocardial stiffness and isovolumic relaxation, during myocardial stunning in different transgenic mice. Methods: Hearts from mice overexpressing thioredoxin-1 and transgenic mice overexpressing thioredoxin-1 with gene mutation in its active site (dominant negative) were compared with hearts from non-transgenic mice after 15-minute global ischemia and 30-minute reperfusion using the Langendorff technique. Systolic and diastolic ventricular function was evaluated and t63 and t93 were calculated as ventricular relaxation index. Results: At 30-minute reperfusion, thioredoxin-1 mice showed a significantly improved contractile state (57.4±4.9 mmHg; p≤0.05 vs. non-transgenic mice) and stiffness (11.8±2.9 mmHg; p≤0.05 vs. non-transgenic mice). Conversely, at the same reperfusion time, dominant negative mice exhibited increased stiffness (37.7±5.5 mmHg; p≤0.05 vs. non-transgenic mice) and slower relaxation (78.2±9.8 ms; p≤0.05 vs. non-transgenic mice). Conclusion: This study reveals the protective role of thioredoxin-1 on myocardial stunning and its pathophysiological importance in mice overexpressing this antioxidant.

Functional and Evolutionary Analysis of the CASPARIAN STRIP MEMBRANE DOMAIN PROTEIN Family.

CASPARIAN STRIP MEMBRANE DOMAIN PROTEINS (CASPs) are four-membrane-span proteins that mediate the deposition of Casparian strips in the endodermis by recruiting the lignin polymerization machinery. CASPs show high stability in their membrane domain, which presents all the hallmarks of a membrane scaffold. Here, we characterized the large family of CASP-like (CASPL) proteins. CASPLs were found in all major divisions of land plants as well as in green algae; homologs outside of the plant kingdom were identified as members of the MARVEL protein family. When ectopically expressed in the endodermis, most CASPLs were able to integrate the CASP membrane domain, which suggests that CASPLs share with CASPs the propensity to form transmembrane scaffolds. Extracellular loops are not necessary for generating the scaffold, since CASP1 was still able to localize correctly when either one of the extracellular loops was deleted. The CASP first extracellular loop was found conserved in euphyllophytes but absent in plants lacking Casparian strips, an observation that may contribute to the study of Casparian strip and root evolution. In Arabidopsis (Arabidopsis thaliana), CASPL showed specific expression in a variety of cell types, such as trichomes, abscission zone cells, peripheral root cap cells, and xylem pole pericycle cells.

Oxidative stress assessed in saliva from patients with acute myocardial infarction. A preliminary study.

UNLABELLED: There is evidence that acute myocardial infarction (AMI) is associated with increasing production of reactive oxygen species and tissue injury. The aim of this study was to assess the presence of oxidative stress indices in saliva 24 and 48h after AMI. MATERIALS AND METHODS: We designed a prospective study comparing salivary levels of biomarkers of oxidative stress in patients with AMI with elevation of the ST segment in electrocardiogram versus clinically healthy subjects. Oxidative stress indices including the rate of oxidation of 2'7' dichlorohydrofluorescein diacetate (DCFH-DA) and the activity of the antioxidant enzyme catalase (CAT) were evaluated in saliva from patients with AMI at 24 and 48 hours. At each sampling time, blood was drawn for serum markers of myocardial infarction. RESULTS: This study included ten patients with acute ST-segment elevation myocardial infarction and ten clinically healthy controls. Mean age was 67.8 +/- 11.1 vs. 48.7 +/- 4.1 years (p < 0.001) and gender was 60% male vs. 50% (p > 0.05) for AMI vs. controls, respectively. Our results demonstrated an increase in the rate of oxidation of DCFH-DA in the myocardial infarction group as compared with controls (p = 0.004), which remained unchanged at 48h. There was no difference in salivary catalase activity between controls and AML subjects at 24h or at 48h post-diagnosis (p = 0.157). The relationship between CAT48 and DCFH-DA48 was fairly significant (r = 0.39; p = 0.053). CONCLUSION: This preliminary study showed that biomarkers of oxidative stress are detectable in saliva of patients with acute myocardial infarction. CLINICAL RELEVANCE: Future studies using a larger population are needed to confirm these observations and to explore the possibility of using the saliva to monitor evolving diagnosis and prognosis in acute coronary syndrome.

A mechanism for localized lignin deposition in the endodermis.

The precise localization of extracellular matrix and cell wall components is of critical importance for multicellular organisms. Lignin is a major cell wall modification that often forms intricate subcellular patterns that are central to cellular function. Yet the mechanisms of lignin polymerization and the subcellular precision of its formation remain enigmatic. Here, we show that the Casparian strip, a lignin-based, paracellular diffusion barrier in plants, forms as a precise, median ring by the concerted action of a specific, localized NADPH oxidase, brought into proximity of localized peroxidases through the action of Casparian strip domain proteins (CASPs). Our findings in Arabidopsis provide a simple mechanistic model of how plant cells regulate lignin formation with subcellular precision. We speculate that scaffolding of NADPH oxidases to the downstream targets of the reactive oxygen species (ROS) that they produce might be a widespread mechanism to ensure specificity and subcellular precision of ROS action within the extracellular matrix.

Oxidative stress assessed in saliva from patients with acute myocardial infarction: a preliminary study

Existe evidencia que permite establecer una asociación entre la generación de especies reactivas del oxígeno y el daño tisular en el síndrome coronario agudo. El objetivo de este trabajo fue detectaren saliva de pacientes con infarto agudo de miocardio (IAM), la presencia de reactantes de estrés oxidativo a las 24 y 48 horas. Materiales y métodos: se efectuó un estudio prospectivo de comparación entre pacientes con IAM con supradesnivel del segmento STen el electrocardiograma y sujetos sin patología clínica evidente. Laproducción de especies reactivas de oxígeno fue evaluada mediantela tasa de oxidación de la 2’7’ diacetato de diclorohidrofluoreceina (DCFH-DA) y la actividad antioxidante de la enzima catalasa (CAT) en saliva de pacientes con IAM a las 24 y 48 h de producido el síndrome coronario agudo. Simultáneamente, se determinaron en suero los biomarcadores diagnósticos de IAM. Resultados: se incorporaron10 pacientes con IAM con supradesnivel del ST que fueron comparados con 10 sujetos del grupo control. La edad promedio fue 67.8 ± 11.1 vs 48.7 ± 4.1 años, respectivamente (p<0.001); el 60 por ciento vs 50 por ciento fueron hombres sin diferencias entre ambos grupos (p>0.05). La media de la velocidad de oxidación de la DCFH-DA fue mayor a las 24 h en los pacientes con IAM (p=0.004). Estas diferencias semantuvieron a las 48 h del infarto sin cambios significativos. No se encontraron diferencias en las medias de actividad de la enzima catalasa entre IAM y control (p>0.05). Se encontró una relación entre CAT48 y DCFH-DA48 (r=0.39; p=0.053). Conclusiones: Enesta población se han detectado reactantes de estrés oxidativo ensaliva de pacientes con IAM. Relevancia clínica: nuevos estudios con mayor número de casos serán necesarios para confirmar estas observaciones y evaluar la utilidad de la saliva en el diagnóstico,evolución y pronóstico del síndrome coronario agudo.

There is evidence that acute myocardial infarction (AMI) is asso-ciated with increasing production of reactive oxygen species andtissue injury. The aim of this study was to assess the presence ofoxidative stress indices in saliva 24 and 48h after AMI. Materialsand methods: We designed a prospective study comparing sali-vary levels of biomarkers of oxidative stress in patients with AMIwith elevation of the ST segment in electrocardiogram versus clin-ically healthy subjects. Oxidative stress indices including the rateof oxidation of 2’7’ dichlorohydrofluorescein diacetate (DCFH-DA) and the activity of the antioxidant enzyme catalase (CAT)were evaluated in saliva from patients with AMI at 24 and 48hours. At each sampling time, blood was drawn for serum mark-ers of myocardial infarction. Results: This study included tenpatients with acute ST-segment elevation myocardial infarctionand ten clinically healthy controls. Mean age was 67.8 ± 11.1 vs.48.7 ± 4.1 years (p<0.001) and gender was 60% male vs. 50%(p>0.05) for AMI vs. controls, respectively. Our results demon-strated an increase in the rate of oxidation of DCFH-DA in themyocardial infarction group as compared with controls (p=0.004),which remained unchanged at 48h. There was no difference insalivary catalase activity between controls and AMI subjects at24h or at 48h post-diagnosis (p=0.157). The relationship betweenCAT48and DCFH-DA48was fairly significant (r=0.39; p=0.053).Conclusion: This preliminary study showed that biomarkers ofoxidative stress are detectable in saliva of patients with acutemyocardial infarction. Clinical Relevance: Future studies using alarger population are needed to confirm these observations and toexplore the possibility of using the saliva to monitor evolving diag-nosis and prognosis in acute coronary syndrome.

Oxidative stress assessed in saliva from patients with acute myocardial infarction: a preliminary study

Existe evidencia que permite establecer una asociación entre la generación de especies reactivas del oxígeno y el daño tisular en el síndrome coronario agudo. El objetivo de este trabajo fue detectaren saliva de pacientes con infarto agudo de miocardio (IAM), la presencia de reactantes de estrés oxidativo a las 24 y 48 horas. Materiales y métodos: se efectuó un estudio prospectivo de comparación entre pacientes con IAM con supradesnivel del segmento STen el electrocardiograma y sujetos sin patología clínica evidente. Laproducción de especies reactivas de oxígeno fue evaluada mediantela tasa de oxidación de la 2Æ7Æ diacetato de diclorohidrofluoreceina (DCFH-DA) y la actividad antioxidante de la enzima catalasa (CAT) en saliva de pacientes con IAM a las 24 y 48 h de producido el síndrome coronario agudo. Simultáneamente, se determinaron en suero los biomarcadores diagnósticos de IAM. Resultados: se incorporaron10 pacientes con IAM con supradesnivel del ST que fueron comparados con 10 sujetos del grupo control. La edad promedio fue 67.8 ± 11.1 vs 48.7 ± 4.1 años, respectivamente (p<0.001); el 60 por ciento vs 50 por ciento fueron hombres sin diferencias entre ambos grupos (p>0.05). La media de la velocidad de oxidación de la DCFH-DA fue mayor a las 24 h en los pacientes con IAM (p=0.004). Estas diferencias semantuvieron a las 48 h del infarto sin cambios significativos. No se encontraron diferencias en las medias de actividad de la enzima catalasa entre IAM y control (p>0.05). Se encontró una relación entre CAT48 y DCFH-DA48 (r=0.39; p=0.053). Conclusiones: Enesta población se han detectado reactantes de estrés oxidativo ensaliva de pacientes con IAM. Relevancia clínica: nuevos estudios con mayor número de casos serán necesarios para confirmar estas observaciones y evaluar la utilidad de la saliva en el diagnóstico,evolución y pronóstico del síndrome coronario agudo.(AU)

There is evidence that acute myocardial infarction (AMI) is asso-ciated with increasing production of reactive oxygen species andtissue injury. The aim of this study was to assess the presence ofoxidative stress indices in saliva 24 and 48h after AMI. Materialsand methods: We designed a prospective study comparing sali-vary levels of biomarkers of oxidative stress in patients with AMIwith elevation of the ST segment in electrocardiogram versus clin-ically healthy subjects. Oxidative stress indices including the rateof oxidation of 2Æ7Æ dichlorohydrofluorescein diacetate (DCFH-DA) and the activity of the antioxidant enzyme catalase (CAT)were evaluated in saliva from patients with AMI at 24 and 48hours. At each sampling time, blood was drawn for serum mark-ers of myocardial infarction. Results: This study included tenpatients with acute ST-segment elevation myocardial infarctionand ten clinically healthy controls. Mean age was 67.8 ± 11.1 vs.48.7 ± 4.1 years (p<0.001) and gender was 60% male vs. 50%(p>0.05) for AMI vs. controls, respectively. Our results demon-strated an increase in the rate of oxidation of DCFH-DA in themyocardial infarction group as compared with controls (p=0.004),which remained unchanged at 48h. There was no difference insalivary catalase activity between controls and AMI subjects at24h or at 48h post-diagnosis (p=0.157). The relationship betweenCAT48and DCFH-DA48was fairly significant (r=0.39; p=0.053).Conclusion: This preliminary study showed that biomarkers ofoxidative stress are detectable in saliva of patients with acutemyocardial infarction. Clinical Relevance: Future studies using alarger population are needed to confirm these observations and toexplore the possibility of using the saliva to monitor evolving diag-nosis and prognosis in acute coronary syndrome.(AU)

Oxidative stress assessed in saliva from patients with acute myocardial infarction. A preliminary study. / Oxidative stress assessed in saliva from patients with acute myocardial infarction. A preliminary study.

UNLABELLED: There is evidence that acute myocardial infarction (AMI) is associated with increasing production of reactive oxygen species and tissue injury. The aim of this study was to assess the presence of oxidative stress indices in saliva 24 and 48h after AMI. MATERIALS AND METHODS: We designed a prospective study comparing salivary levels of biomarkers of oxidative stress in patients with AMI with elevation of the ST segment in electrocardiogram versus clinically healthy subjects. Oxidative stress indices including the rate of oxidation of 27 dichlorohydrofluorescein diacetate (DCFH-DA) and the activity of the antioxidant enzyme catalase (CAT) were evaluated in saliva from patients with AMI at 24 and 48 hours. At each sampling time, blood was drawn for serum markers of myocardial infarction. RESULTS: This study included ten patients with acute ST-segment elevation myocardial infarction and ten clinically healthy controls. Mean age was 67.8 +/- 11.1 vs. 48.7 +/- 4.1 years (p < 0.001) and gender was 60

male vs. 50

(p > 0.05) for AMI vs. controls, respectively. Our results demonstrated an increase in the rate of oxidation of DCFH-DA in the myocardial infarction group as compared with controls (p = 0.004), which remained unchanged at 48h. There was no difference in salivary catalase activity between controls and AML subjects at 24h or at 48h post-diagnosis (p = 0.157). The relationship between CAT48 and DCFH-DA48 was fairly significant (r = 0.39; p = 0.053). CONCLUSION: This preliminary study showed that biomarkers of oxidative stress are detectable in saliva of patients with acute myocardial infarction. CLINICAL RELEVANCE: Future studies using a larger population are needed to confirm these observations and to explore the possibility of using the saliva to monitor evolving diagnosis and prognosis in acute coronary syndrome.