A Decrease in Branched-Chain Amino Acids after a Competitive Male Professional Volleyball Game-A Metabolomic-Based Approach.

A competitive volleyball game is a highly metabolic and physically demanding event for professional players. This study aimed to investigate whether a single game at the end of a preseason promotes changes in the biochemical markers of physical exercise responses and the metabolomic profile of professional volleyball players. This cross-sectional study included 13 male Brazilian professional volleyball players. Food intake, body composition, heart rate, physical movement variables, and blood biochemical indicators were evaluated. For non-target metabolomic analysis, serum samples were subjected to 500 MHz Nuclear Magnetic Resonance. Data analysis showed no significant difference in the biochemical indicators after the game (p > 0.05). The level of metabolites present in the groups of the main components (ß-hydroxybutyrate, arginine/lysine, isoleucine, leucine, and valine) had decreased after the game. However, formic acid and histidine levels increased. Among the compounds not part of the main components, hypoxanthine and tyrosine increased, whereas low-density lipoprotein and very low-density lipoprotein levels decreased. After the game, the metabolomic profiles of players showed significant negative variations in essential amino acids (leucine, valine, and isoleucine). These decreases might be influenced by athlete diet and reduced glycogen storage due to lower carbohydrate intake, potentially impacting serum-essential amino acid levels via oxidation in skeletal muscle. The study provides insights for developing metabolic compensation strategies in athletes.

Chronic alcohol and nicotine consumption as catalyst for systemic inflammatory storm and bone destruction in apical periodontitis.

AIM: To assess the periapical alveolar bone pattern and the serum levels of proinflammatory cytokines, biochemical markers and metabolites in rats subjected to chronic alcohol and nicotine consumption and induced apical periodontitis. METHODOLOGY: Twenty-eight male Wistar rats were divided into four groups: Control, Alcohol, Nicotine and Alcohol+Nicotine. The alcohol groups were exposed to self-administration of a 25% alcohol solution, while the other groups were given only filtered water. The nicotine groups received daily intraperitoneal injections of a nicotine solution (0.19 µL of nicotine/mL), whereas the other groups received saline solution. Periapical lesions were induced by exposing the pulps of the left mandibular first molars for 28 days. After euthanasia, the mandibles were removed and the percentage bone volume, bone mineral density, trabecular thickness, trabecular separation and trabecular number of the periapical bone were measured using micro-computed tomography images. Serum samples were collected for analysis of proinflammatory cytokines (IL-1ß, IL-4, IL-6 and TNF-α), biochemical and metabolomic analysis. Statistical analysis was performed with a significance level of 5%. Nonparametric data were analysed using the Kruskal-Wallis test followed by Dunn's test, while one-way anova followed by Tukey's test was performed for parametric data. RESULTS: The groups exposed to alcohol or nicotine consumption exhibited an altered bone pattern indicating lower bone density and higher levels of IL-1ß, IL-6 and TNF-α compared to the Control group (p < .05). Significant differences were observed among the groups in the levels of aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase, cholesterol, triglycerides, urea, creatinine, albumin, uric acid, bilirubin and calcium. Metabolomic analysis revealed significant differences in glycine, phosphocholine, lysine, lactate, valine, pyruvate and lipids (CH2 CH2 CO), n(CH2 ) and n(CH3 ). Most of these parameters were even more altered in the simultaneous consumption of both substances compared to single consumption. CONCLUSION: Alcohol and nicotine chronic consumption altered several metabolic markers, impaired liver and kidney function, increased the production of systemic proinflammatory mediators and harmed the periapical bone microarchitecture in the presence of apical periodontitis. The simultaneous consumption of alcohol and nicotine intensified these detrimental effects.

Salivary Metabolites in Patients with Mucopolysaccharidosis

ABSTRACT Objective: To identify the salivary metabolites profile of Mucopolysaccharidosis (MPS) types I, II, IV, and VI patients. Material and Methods: The participants were asked to refrain from eating and drinking for one hour before sampling, performed between 7:30 and 9:00 a.m. Samples were centrifuged at 10.000 × g for 60 min at 4°C, and the supernatants (500µl) were stored at −80°C until NMR analysis. The salivary proton nuclear magnetic resonance (1H-NMR) spectra were acquired in a 500 MHz spectrometer, and TOCSY experiments were used to confirm and assign metabolites. Data were analyzed descriptively. Results: Differences in salivary metabolites were found among MPS types and the control, such as lactate, propionate, alanine, and N-acetyl sugar. Understanding these metabolite changes may contribute to precision medicine and early detection of mucopolysaccharidosis and its monitoring. Conclusion: The composition of low molecular weight salivary metabolites of mucopolysaccharidosis subjects may present specific features compared to healthy controls.

Comparison of the effects of pea protein and whey protein on the metabolic profile of soccer athletes: a randomized, double-blind, crossover trial.

Introduction: Pea protein (PP) concentrate is a plant-based alternative to animal protein sources, such as whey protein (WP). In addition to its valuable amino acid composition, PP has a low environmental impact, making it a sustainable, nutritious, and viable alternative for enhanced sports performance, such as in soccer. PP Therefore, this study aimed to evaluate the effects of PP and WP supplementation on biochemical and metabolic parameters in soccer players. Methods: Twelve male under-20 soccer players were included in this double-blind, randomized crossover intervention study. For 10 consecutive days, each participant received either 0.5 g/kg of the PP or WP supplementation after training, starting 7 days before the test game, and continuing until 2 days after. After a 4-day washout period, the athletes switched groups and the intervention was restarted. Blood samples were collected before and after the game, as well as 24 h, 48 h, and 72 h intervals thereafter. Creatine kinase (CK), aspartate transaminase, alanine transaminase (ALT), lactate (LA), urea, creatinine, and uric acid were analyzed using commercial kits. Exploratory metabolic profiling of the serum samples was performed using nuclear magnetic resonance spectroscopy. Results: A comparison of biochemical markers showed that the PP group had lower CK in the post-game moment, 24 h, and 48 h. Lower LA in the post-game moment, and lower ALT in the post-game moment and at 24 h. Of the 48 metabolites analyzed, 22 showed significant differences between the time points, such as amino acids, ketone bodies, and glucose metabolism. Glutamate and lactate levels significantly increased between the pre- and post-game moments in the WP group. After the game, the WP group exhibited reduced levels of metabolites such as arginine and taurine, whereas no such change was observed in the PP group. There was no difference in metabolites 72 h after the game. Conclusions: Despite the slight advantage of the PP group in specific biochemical markers, these differences are not sufficient to justify the choice of a particular type of protein. However, the results highlight the viability of plant protein as a potential alternative to animal protein without compromising athletic performance or recovery.

Integrated NMR and MS Analysis of the Plasma Metabolome Reveals Major Changes in One-Carbon, Lipid, and Amino Acid Metabolism in Severe and Fatal Cases of COVID-19.

Brazil has the second-highest COVID-19 death rate worldwide, and Rio de Janeiro is among the states with the highest rate in the country. Although vaccine coverage has been achieved, it is anticipated that COVID-19 will transition into an endemic disease. It is concerning that the molecular mechanisms underlying clinical evolution from mild to severe disease, as well as the mechanisms leading to long COVID-19, are not yet fully understood. NMR and MS-based metabolomics were used to identify metabolites associated with COVID-19 pathophysiology and disease outcome. Severe COVID-19 cases (n = 35) were enrolled in two reference centers in Rio de Janeiro within 72 h of ICU admission, alongside 12 non-infected control subjects. COVID-19 patients were grouped into survivors (n = 18) and non-survivors (n = 17). Choline-related metabolites, serine, glycine, and betaine, were reduced in severe COVID-19, indicating dysregulation in methyl donors. Non-survivors had higher levels of creatine/creatinine, 4-hydroxyproline, gluconic acid, and N-acetylserine, indicating liver and kidney dysfunction. Several changes were greater in women; thus, patients' sex should be considered in pandemic surveillance to achieve better disease stratification and improve outcomes. These metabolic alterations may be useful to monitor organ (dys) function and to understand the pathophysiology of acute and possibly post-acute COVID-19 syndromes.

Metabolic Adaptations Correlated with Antibody Response after Immunization with Inactivated SARS-CoV-2 in Brazilian Subjects.

The adsorbed vaccine SARS-CoV-2 (inactivated) produced by Sinovac (SV) was the first vaccine against COVID-19 to be used in Brazil. To understand the metabolic effects of SV in Brazilian subjects, NMR-based metabolomics was used, and the immune response was studied in Brazilian subjects. Forty adults without (group-, n = 23) and with previous COVID-19 infection (group+, n = 17) were followed-up for 90 days postcompletion of the vaccine regimen. After 90 days, our results showed that subjects had increased levels of lipoproteins, lipids, and N-acetylation of glycoproteins (NAG) as well as decreased levels of amino acids, lactate, citrate, and 3-hydroxypropionate. NAG and threonine were the highest correlated metabolites with N and S proteins, and neutralizing Ab levels. This study sheds light on the immunometabolism associated with the use of SV in Brazilian subjects from Rio de Janeiro and identifies potential metabolic markers associated with the immune status.

Oral Health Policy in Brazil: changes and ruptures during the period 2018-2021. / Política de Saúde Bucal no Brasil: transformações e rupturas entre 2018-2021.

This study analyzed the implementation of Brazil's National Oral Health Policy during the period 2018-2021, covering institutional actions, implementation of public dental services, results achieved, and federal funding. We conducted a retrospective descriptive study using documentary analysis and secondary data obtained from institutional websites, government information systems, and reports published by dental organizations. The findings show a significant reduction in funding between 2020 and 2021 and declining performance against indicators since 2018, such as coverage of first dental appointments and group supervised tooth brushing, which stood at 1.8% and 0.02%, respectively, in 2021. Federal funding dropped in 2018 and 2019 (8.45%), followed by an increase in 2020 (59.53%) and decrease in 2021 (-5.18%). The study period was marked by economic and political crises aggravated by the COVID-19 pandemic. This context influenced the functioning of health services in Brazil. There was a sharp reduction in performance against oral health indicators, while performance in primary health care and specialized care services remained stable.

Analisou-se a implementação da Política de Saúde Bucal no Brasil no período 2018-2021, através das ações institucionais, implantação dos serviços, resultados alcançados e financiamento federal. Estudo de monitoramento, a partir da análise documental e de dados secundários, obtidos em sites institucionais, sistemas de informações governamentais e notícias publicadas por entidades odontológicas. Todos os indicadores de resultados monitorados apresentaram expressiva redução dos valores entre 2020-2021, com agravamento desde 2018, como a cobertura da primeira consulta odontológica e ação coletiva de escovação dental supervisionada, que chegou a 1,8% e 0,02% em 2021, respectivamente. Observa-se uma queda do financiamento federal nos anos 2018-2019 (8,45%), com crescimento em 2020 (59,53%) e nova diminuição em 2021 (5,18%). O período analisado foi marcado por crise econômica e política, agravadas pela crise sanitária, decorrente da pandemia do COVID-19. Contexto que influenciou o funcionamento dos serviços de saúde no Brasil. No caso particular da saúde bucal, verificou-se progressiva e acentuada redução dos resultados, ainda que a implantação dos serviços de atenção básica e especializada tenha se mantido estável.

Política de Saúde Bucal no Brasil: transformações e rupturas entre 2018-2021 / Oral Health Policy in Brazil: changes and ruptures during the period 2018-2021

Resumo Analisou-se a implementação da Política de Saúde Bucal no Brasil no período 2018-2021, através das ações institucionais, implantação dos serviços, resultados alcançados e financiamento federal. Estudo de monitoramento, a partir da análise documental e de dados secundários, obtidos em sites institucionais, sistemas de informações governamentais e notícias publicadas por entidades odontológicas. Todos os indicadores de resultados monitorados apresentaram expressiva redução dos valores entre 2020-2021, com agravamento desde 2018, como a cobertura da primeira consulta odontológica e ação coletiva de escovação dental supervisionada, que chegou a 1,8% e 0,02% em 2021, respectivamente. Observa-se uma queda do financiamento federal nos anos 2018-2019 (8,45%), com crescimento em 2020 (59,53%) e nova diminuição em 2021 (5,18%). O período analisado foi marcado por crise econômica e política, agravadas pela crise sanitária, decorrente da pandemia do COVID-19. Contexto que influenciou o funcionamento dos serviços de saúde no Brasil. No caso particular da saúde bucal, verificou-se progressiva e acentuada redução dos resultados, ainda que a implantação dos serviços de atenção básica e especializada tenha se mantido estável.

Abstract This study analyzed the implementation of Brazil's National Oral Health Policy during the period 2018-2021, covering institutional actions, implementation of public dental services, results achieved, and federal funding. We conducted a retrospective descriptive study using documentary analysis and secondary data obtained from institutional websites, government information systems, and reports published by dental organizations. The findings show a significant reduction in funding between 2020 and 2021 and declining performance against indicators since 2018, such as coverage of first dental appointments and group supervised tooth brushing, which stood at 1.8% and 0.02%, respectively, in 2021. Federal funding dropped in 2018 and 2019 (8.45%), followed by an increase in 2020 (59.53%) and decrease in 2021 (-5.18%). The study period was marked by economic and political crises aggravated by the COVID-19 pandemic. This context influenced the functioning of health services in Brazil. There was a sharp reduction in performance against oral health indicators, while performance in primary health care and specialized care services remained stable.

NMR-Based Metabolomics Demonstrates a Metabolic Change during Early Developmental Stages from Healthy Infants to Young Children.

The present study aims to identify the salivary metabolic profile of healthy infants and young children, and to correlate this with age, salivary gland maturation, and dentition. Forty-eight children were selected after clinical evaluation in which all intraoral structures were examined. Total unstimulated saliva was collected, and salivary metabolites were analyzed by 1H Nuclear Magnetic Resonance (NMR) at 25 °C. Partial least squares discriminant analysis (PLS-DA), orthogonal PLS-DA (O-PLS-DA), and univariate analysis were used, adopting a 95% confidence interval. The study showed a distinct salivary metabolomic profile related to age and developmental phase. The saliva of children in the pre-eruption teeth period showed a different metabolite profile than that of children after the eruption. However, more evident changes were observed in the saliva profile of children older than 30 months. Alanine, choline, ethanol, lactate, and sugar region were found in higher levels in the saliva of patients before 30 months old. Acetate, N-acetyl sugar, butyrate, caproate, creatinine, leucine, phenylalanine, propionate, valine, succinate, and valerate were found to be more abundant in the saliva of children after 30 months old. The saliva profile is a result of changes in age and dental eruption, and these findings can be useful for monitoring the physiological changes that occur in infancy.

Salivary Metabolomic Analysis Reveals Amino Acid Metabolism Shift in SARS-CoV-2 Virus Activity and Post-Infection Condition.

The SARS-CoV-2 virus primarily infects salivary glands suggesting a change in the saliva metabolite profile; this shift may be used as a monitoring instrument during SARS-CoV-2 infection. The present study aims to determine the salivary metabolomic profile of patients with and post-SARS-CoV-19 infection. Patients were without (PCR-), with SARS-CoV-2 (PCR+), or post-SARS-CoV-2 infection. Unstimulated whole saliva was collected, and the 1H spectra were acquired in a 500 MHz Bruker nuclear magnetic resonance spectrometer at 25 °C. They were subjected to multivariate analysis using principal component analysis (PCA) and partial least squares discriminant analysis (PLS-DA), as well as univariate analysis through t-tests (SPSS 20.0, IL, USA), with a significance level of p < 0.05. A distinction was found when comparing PCR- subjects to those with SARS-CoV-2 infection. When comparing the three groups, the PLS-DA cross-validation presented satisfactory accuracy (ACC = 0.69, R2 = 0.39, Q2 = 0.08). Seventeen metabolites were found in different proportions among the groups. The results suggested the downregulation of major amino acid levels, such as alanine, glutamine, histidine, leucine, lysine, phenylalanine, and proline in the PCR+ group compared to the PCR- ones. In addition, acetate, valerate, and capronic acid were higher in PCR- patients than in PCR+. Sucrose and butyrate were higher in post-SARS-CoV-2 infection compared to PCR-. In general, a reduction in amino acids was observed in subjects with and post-SARS-CoV-2 disease. The salivary metabolomic strategy NMR-based was able to differentiate between non-infected individuals and those with acute and post-SARS-CoV-19 infection.

Salivary metabolomic profile in adolescents with juvenile systemic lupus erythematosus.

The aim of this study was to characterize the salivary metabolomic profile in adolescents with juvenile systemic lupus erythematosus (jSLE). A total of 24 adolescents with jSLE (15.92 ± 2.06 years) and 12 systemically healthy controls (15.25 ± 2.7 years) were included in the study. Participants underwent rheumatologic testing and periodontal examination, with the recording of plaque index (PI), probing depth (PD), clinical attachment level (CAL), and bleeding on probing index (BPI). Unstimulated whole saliva was collected from both groups and stored at -80 ºC. The salivary proton nuclear magnetic resonance (1H-NMR) spectra were acquired in a spectrometer operating at 500 MHz. Partial least squared discriminant analysis (PLS-DA) and orthogonal PLS-DA (O-PLS-DA) were used for statistical analysis. Mean CAL and PI were significantly increased in the group with jSLE (p < 0.01). Patients with jSLE presented a significantly different salivary metabolic profile (accuracy = 0.54; R2 = 0.86; Q2 = -0.293), significantly higher salivary levels of N-acetyl sugars, and significantly reduced levels of phenylalanine, glycine, taurine, hydroxybutyrate, and valerate compared with healthy controls (p < 0.05). It is suggested that the salivary metabolomic profile analyzed by 1H NMR in patients with jSLE presents a different fingerprint that the systemically healthy subjects. Integrating the variation of metabolites with the identification of the metabolic pathways involved seems to provide a better understanding of the influence of systemic disease on salivary metabolites.

A critical review on the association of hyposalivation and dental caries in children and adolescents.

OBJECTIVE: The purpose of this critical review is to assess if children and adolescents with hyposalivation are more affected by dental caries than those with normal flow rate. DESIGN: A literature search was performed using keywords and MeSH terms related to hyposalivation and dental caries in the Medline/PubMed, Web of Science, Cochrane Library, Scopus, LILACS/BBO databases and in gray literature without language or date restrictions until March 2022. Observational studies that accessed the presence of dental caries in patients up to 18 years-old with hyposalivation and compared with a control group (normal salivation rate) were considered eligible. The results from search were imported to EndNote Web, where duplicates were removed followed by title/abstract and full text analysis. RESULTS: A total of 12,236 non-duplicated studies were found and 14 fulfilled the criteria and were included in the present review, 9 cross-sectional and 5 cohorts. Stimulated salivary flow rates were assessed in 3644 participants, aged 3-17 years. Three cohort and three cross-sectional studies observed association between low salivary flow rates and the presence of dental caries, while the other 9 included articles did not verify this association. However, the absence of a standard criteria for the hyposalivation classification in young patients was observed and brough light to this important limitation among the studies. CONCLUSION: The salivary flow rate estimation for caries risk assessment must be the target of further studies to make possible and reliable, homogeneous, and unbiasedly assessment of the association between hyposalivation and dental caries in young patients.

NMR analysis: potential and challenges as a homeopathic basic research tool

Homeopathic ultra-diluted solutions surpass the threshold of matter dispersion and, consequently, their chemical constitution is similar to inert solvent. Nevertheless, randomized clinical trials have shown that the clinical effects of these homeopathic medicines are superior to placebo1. Nuclear magnetic resonance (NMR) is one of the most promising techniques to detect physicochemical alterations induced by homeopathic procedures2,3. Aims: To investigate T2 NMR relaxation times of Zincum metallicumand lactose dynamized samples. Methodology: Zincum metallicumsamples were ground until 6dH using lactose as an excipient. Subsequently, these samples were dynamized with ultrapure water to produce 8dH, 9dH, 10dH,and 11dH. Lactose dynamized samples (6dH-11dH) were used as control. Aliquots of 540µl of each sample were diluted with 60µl of deuterated water (D2O) in 5mm tubes. The analyses were carried out in Bruker Ascend TM 500MHZ spectrometer at 288 K. Results and discussion: The Zincum metallicumand lactose T2 relaxation times were very similar, except for Zincum metallicum8dH, which presented a value of 1.226 in comparison to 1.036 of lactose 8dH. The following T2 values were registered: 1.287 -9dH; 1.413 -10dH; 1.467 -11dH, and 1.303 -9dH; 1.400 ­10dH; 1.350 -11dH, for Zincum metallicumand lactose, respectively. The differences detected in 8dH samples are probably due to the presence of lactose in the first dilution step, in which 1 part of the 6dH triturated mixture was diluted in 9 parts of water, to prepare 7dH. Following this homeopathic procedure, 8dH solutions remain around 1% of lactose which could be influenced by the T2 values registered.Conclusion: These preliminary results showed the possibility to apply the NMR technique to evaluate the influence of dynamization in the relaxation parameters. Further studies should be carried out with other potencies and/or other homeopathic substances, in addition to the evaluation of T1 and the T1/T2 parameters, as previously described by other groups.

Backbone 1H, 15N, and 13C resonance assignments of the non-structural protein NS2B of Zika virus.

Zika virus (ZIKV) emerged as a global public health concern due to its relationship with severe neurological disorders. Non-structural (NS) proteins of ZIKV are essential for viral replication, regulatory function, and subversion of host responses. NS2B is a membrane protein responsible for the regulation of viral protease activity. This protein has transmembrane domains critical for the localization of viral protease to the endoplasmic reticulum membrane and a hydrophilic domain essential for folding, recruitment, and protease activity. Therefore, NS2B is considered a cofactor of viral protease which processes viral polyprotein and is essential for virus replication, making it an attractive antiviral drug target. Here, we report the backbone 1H, 15N, 13C resonance assignments of the full-length NS2B by high-resolution NMR. The backbone assignment will be necessary for determining the three-dimensional structure and backbone dynamics of NS2B, interaction mapping and screening potential of antiviral drugs against ZIKV and related pathogenic flaviviruses.

Impact of Precompetitive Training on Metabolites in Modern Pentathletes.

PURPOSE: Modern pentathlon is a multidisciplinary sport that involves exhaustive training which can cause tissue damage and metabolic changes. However, few studies have evaluated the metabolic changes that occur in pentathletes. Accordingly, we aimed to evaluate the metabolomic profile of pentathletes during a 3-week training period before competition using nuclear magnetic resonance. METHODS: Blood samples from 6 members of a Brazilian modern pentathlon team were collected at the beginning (Pre1, Pre2, and Pre3) and end (Post1, Post2, and Post3) of each week. Low molecular-weight metabolite profiles were analyzed by nuclear magnetic resonance spectroscopy, and biochemical markers were assessed using enzyme-linked immunosorbent assays. Data were assessed using partial least-squares discriminant analysis and univariate statistical model. RESULTS: Metabolic changes were observed between pre- and postdata of each week and over the 3 weeks before the competition in the partial least-squares discriminant analysis. Creatine kinase concentration increased in the first 2 weeks (P = .045 and P = .039), but there was no difference in the last week (P > .05). Lactate levels increased significantly after training in each week (P < .001). Cortisol levels at Post3 were different from all other time points (P < .05) and the concentrations of peroxides increased over the weeks (P < .05). Among all metabolites, sarcosine showed the greatest differences (P = .004) in the pretraining and posttraining periods of the 3 weeks. CONCLUSION: Serum analysis of athletes using nuclear magnetic resonance showed metabolic changes depending on the intensity of the training performed each week.

Salivary metabolomic profile in adolescents with juvenile systemic lupus erythematosus

Abstract The aim of this study was to characterize the salivary metabolomic profile in adolescents with juvenile systemic lupus erythematosus (jSLE). A total of 24 adolescents with jSLE (15.92 ± 2.06 years) and 12 systemically healthy controls (15.25 ± 2.7 years) were included in the study. Participants underwent rheumatologic testing and periodontal examination, with the recording of plaque index (PI), probing depth (PD), clinical attachment level (CAL), and bleeding on probing index (BPI). Unstimulated whole saliva was collected from both groups and stored at -80 ºC. The salivary proton nuclear magnetic resonance (1H-NMR) spectra were acquired in a spectrometer operating at 500 MHz. Partial least squared discriminant analysis (PLS-DA) and orthogonal PLS-DA (O-PLS-DA) were used for statistical analysis. Mean CAL and PI were significantly increased in the group with jSLE (p < 0.01). Patients with jSLE presented a significantly different salivary metabolic profile (accuracy = 0.54; R2 = 0.86; Q2 = -0.293), significantly higher salivary levels of N-acetyl sugars, and significantly reduced levels of phenylalanine, glycine, taurine, hydroxybutyrate, and valerate compared with healthy controls (p < 0.05). It is suggested that the salivary metabolomic profile analyzed by 1H NMR in patients with jSLE presents a different fingerprint that the systemically healthy subjects. Integrating the variation of metabolites with the identification of the metabolic pathways involved seems to provide a better understanding of the influence of systemic disease on salivary metabolites.

The bacterial microbiome and metabolome in caries progression and arrest.

Aim: This in vivo experimental study investigated bacterial microbiome and metabolome longitudinal changes associated with enamel caries lesion progression and arrest. Methods: We induced natural caries activity in three caries-free volunteers prior to four premolar extractions for orthodontic reasons. The experimental model included placement of a modified orthodontic band on smooth surfaces and a mesh on occlusal surfaces. We applied the caries-inducing protocol for 4- and 6-weeks, and subsequently promoted caries lesion arrest via a 2-week toothbrushing period. Lesions were verified clinically and quantitated via micro-CT enamel density measurements. The biofilm microbial composition was determined via 16S rRNA gene Illumina sequencing and NMR spectrometry was used for metabolomics. Results: Biofilm maturation and caries lesion progression were characterized by an increase in Gram-negative anaerobes, including Veillonella and Prevotella. Streptococcus was associated caries lesion progression, while a more equal distribution of Streptococcus, Bifidobacterium, Atopobium, Prevotella, Veillonella, and Saccharibacteria (TM7) characterized arrest. Lactate, acetate, pyruvate, alanine, valine, and sugars were more abundant in mature biofilms compared to newly formed biofilms. Conclusions: These longitudinal bacterial microbiome and metabolome results provide novel mechanistic insights into the role of the biofilm in caries progression and arrest and offer promising candidate biomarkers for validation in future studies.

Conformational dynamics of Tetracenomycin aromatase/cyclase regulate polyketide binding and enzyme aggregation propensity.

BACKGROUND: The N-terminal domain of Tetracenomycin aromatase/cyclase (TcmN), an enzyme derived from Streptomyces glaucescens, is involved in polyketide cyclization, aromatization, and folding. Polyketides are a diverse class of secondary metabolites produced by certain groups of bacteria, fungi, and plants with various pharmaceutical applications. Examples include antibiotics, such as tetracycline, and anticancer drugs, such as doxorubicin. Because TcmN is a promising enzyme for in vitro production of polyketides, it is important to identify conditions that enhance its thermal resistance and optimize its function. METHODS: TcmN unfolding, stability, and dynamics were evaluated by fluorescence spectroscopy, circular dichroism, nuclear magnetic resonance 15N relaxation experiments, and microsecond molecular dynamics (MD) simulations. RESULTS: TcmN thermal resistance was enhanced at low protein and high salt concentrations, was pH-dependent, and denaturation was irreversible. Conformational dynamics on the µs-ms timescale were detected for residues in the substrate-binding cavity, and two predominant conformers representing opened and closed cavity states were observed in the MD simulations. CONCLUSION: Based on the results, a mechanism was proposed in which the thermodynamics and kinetics of the TcmN conformational equilibrium modulate enzyme function by favoring ligand binding and avoiding aggregation. GENERAL SIGNIFICANCE: Understanding the principles underlying TcmN stability and dynamics may help in designing mutants with optimal properties for biotechnological applications.

Effect of antihistamine-containing syrup on salivary metabolites: an in vitro and in vivo study.

This study tested the null hypothesis that antihistamine-containing syrup does not change salivary metabolites in vitro and in vivo. For the in vitro experiments, saliva from 10 volunteers was mixed with a syrup or pill suspension of loratadine (1 mg/ml Claritin®, Schering-Plough, Rio de Janeiro, Brazil). For the in vivo experiment, 10 volunteers performed a mouth rinse with 10 mL of antihistamine syrup (Claritin®; Schering-Plough, Rio de Janeiro, Brazil) for 20 seconds and then discarded the rinse water. After 20 seconds, 5 mL of unstimulated whole saliva was spit into a plastic tube kept on ice. The protein profile of in vitro and in vivo experiments was analyzed using 12% sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The samples were also analyzed by nuclear magnetic resonance (NMR) spectroscopy, followed by Principal Component Analysis and Wilcoxon test (p < 0.05). There were differences in salivary metabolites after syrup interaction. The salivary concentrations of acetate, n-caproate, arginine, glutamate, and lysine among other metabolites were reduced with the syrup in both in vivo and in vitro experiments (p < 0.05), but no differences were observed when the pill suspension was used (p > 0.05). Similar changes in metabolite profiles were observed in both in vitro and in vivo experiments. Electrophoresis revealed no difference in the salivary protein pattern. The null hypothesis was rejected because the intake of syrup medicine changes the salivary composition and influences oral homeostasis and susceptibility to oral diseases.

Salivary metabolome of children and adolescents under peritoneal dialysis.

OBJECTIVE: To study the influence of peritoneal dialysis (PD) on the salivary metabolite profile of children and adolescents with renal failure. MATERIALS AND METHODS: Healthy children/adolescents (n = 31; mean age: 12.18 ± 3.76) and children/adolescents subjected to PD (n = 12; mean age: 10.10 ± 4.25) were recruited. Oral health status assessed by the dmft/DMFT and Volpe-Manhold calculus indices. The 1H spectra were acquired in a 600-MHz Bruker nuclear magnetic resonance spectrometer and were subjected to multivariate analysis using partial least squares discriminant analysis (PLS-DA), orthogonal PLS-DA (O-PLS-DA), and univariate analysis through chi-square and t tests (SPSS 20.0, IL, USA), with a significance level of p < 0.05. RESULTS: A similar caries pattern (p = 0.57; chi-square test) was observed between the healthy (dmft = 0.72 ± 1.28 and DMFT 0.93 ± 2.30) and PD groups (dmft = 2.14 ± 3.67, DMFT 0.33 ± 0.71) and dental calculus (p > 0.05, t test). PLS-DA and O-PLS-DA were able to distinguish both groups (ACC = 0.85, R2 = 0.80, Q2 = 0.15). Salivary metabolites decrease in creatine, propionate, and sugar levels in the PD group and an increase in creatinine, butyrate, and lactate levels when compared with the healthy group. CONCLUSIONS: Children and adolescents subjected to PD have a different salivary metabolic profile from that of their healthy subjects. CLINICAL RELEVANCE: Complications of peritoneal dialysis procedures could be monitored by proper knowledge of saliva characteristics as predictors of peritonitis-related outcome. The use of metabolomics in pediatric nephrology may be an innovative methodology for the early diagnosis and monitoring of kidney diseases.