Antibody isotype epitope mapping of SARS-CoV-2 Spike RBD protein: Targets for COVID-19 symptomatology and disease control.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) still poses a challenge for biomedicine and public health. To advance the development of effective diagnostic, prognostic, and preventive interventions, our study focused on high-throughput antibody binding epitope mapping of the SARS-CoV-2 spike RBD protein by IgA, IgM and IgG antibodies in saliva and sera of different cohorts from healthy uninfected individuals to SARS-CoV-2-infected unvaccinated and vaccinated asymptomatic, recovered, nonsevere, and severe patients. Identified candidate diagnostic (455-LFRKSNLKPFERD-467), prognostic (395-VYADSFVIRGDEV-407-C-KLH, 332-ITNLCPFGEV-342-C-KLH, 352-AWNRKRI-358-C-KLH, 524-VCGPKKSTNLVKN-536-KLH), and protective (MKLLE-487-NCYFPLQSYGFQPTNGVG-504-GGGGS-446-GGNYNYLYRLFRKSNLKPFERD-467) epitopes were validated with sera from prevaccine and postvaccine cohorts. The results identified neutralizing epitopes and support that antibody recognition of linear B-cell epitopes in RBD protein is associated with antibody isotype and disease symptomatology. The findings in asymptomatic individuals suggest a role for anti-RBD antibodies in the protective response against SARS-CoV-2. The possibility of translating results into diagnostic interventions for the early diagnosis of asymptomatic individuals and prognosis of disease severity provides new tools for COVID-19 surveillance and evaluation of risks in hospitalized patients. These results, together with other approaches, may contribute to the development of new vaccines for the control of COVID-19 and other coronavirus-related diseases using a quantum vaccinomics approach through the combination of protective epitopes.

Evaluation of the presence of gingivitis as confounding factor in assessing inflammatory status in serum and saliva of dogs with diabetes mellitus.

The aim of this study was to evaluate the changes in the serum and salivary inflammatory markers induced by Diabetes mellitus (DM) in dogs and to assess the possible confounding effect of gingivitis. A panel of 13 cytokines was measured in the serum and saliva of dogs diagnosed with DM and compared with healthy dogs without gingivitis (control group 1; CG1) and dogs with gingivitis but otherwise healthy (control group 2; CG2). The results of the present study showed statistically significantly higher levels of IL-8, KC-like and MCP1 in the serum of dogs with DM compared to CG1 dogs. In the case of saliva, the DM group presented statistically higher GM-CSF, IL6, IL15, and MCP1 levels compared to CG1, and lower KC-like chemokine compared to CG2. Finally, gingivitis produced changes in saliva, with salivary levels of GM-CSF, IL-6, IL-7, IL-15, IP-10, KC-like, IL-10, IL-18, MCP1, TNFα being statistically significantly higher in the saliva of CG2 dogs compared to CG1. The results of the present study indicate that dogs with DM have altered cytokine levels in serum and saliva compared to healthy dogs. In addition, this study highlights the importance of taking oral health into account when determining cytokines in dogs, as gingivitis can significantly alter their concentrations. .

Oxytocin measurements in saliva: an analytical perspective.

Oxytocin has traditionally been known for its physiological effects on muscle contraction associated with birth and lactation, but in the last years is widely used as a biomarker of "positive experiences" in psychology and behavior. Different types of samples have been used for oxytocin measurements with saliva samples having the particular advantage of an easy and non-stressful collection. However, the low concentration of oxytocin in saliva can represent a limitation for its use. For this reason, sensitive assays and even a previous sample treatment in some cases are required for saliva oxytocin quantification. In addition, the lack of standardized and generally agreed-upon approach to peripheral oxytocin measurement leads to large discrepancies between different laboratories, that use different sample treatment protocols and different assays. The main objectives of this review are to describe the current status of the use of saliva for oxytocin measurement, provide details of the different sample processing techniques that can be applied and inform about the analytical techniques and assays available in different animal species, and also in humans for comparative purposes. It is expected that this information can contribute to an increase in the knowledge about the measurements of oxytocin in saliva and to its wider use in the future.

Acute phase proteins and total antioxidant capacity in free-roaming cats infected by pathogenic leptospires.

BACKGROUND: Leptospirosis is a neglected but widespread zoonotic disease throughout the world. Most mammals are hosts of Leptospira spp., including domestic cats, species in which no consensus has been reached on the clinical presentation or diagnosis of the disease. The study of acute-phase proteins (APPs) and biomarkers of oxidative status would contribute to knowledge about the disease in cats. This report evaluated four APPs: Serum amyloid A-SAA, Haptoglobin-Hp, albumin and Paraoxonase 1-PON1 and the antioxidant response through Total Antioxidant Capacity-TAC, in 32 free-roaming cats. Cats were classified as seroreactive for anti-leptospiral antibodies (group 1, n = 8), infected with Leptospira spp (group 2, n = 5) and leptospires-free cats (group 3, n = 19). RESULTS: SAA differences were observed between groups 1 and 2 (p-value = 0.01) and between groups 2 and 3 (p-value = 0.0001). Hp concentration differences were only detected between groups 2 and 3 (p-value = 0.001). Albumin concentrations only differed between groups 1 and 3 (p-value = 0.017) and 2 and 3 (p-value < 0.005). Cats in groups 1 (p-value < 0.005) and 2 (p-value < 0.005) had lower PON1 concentrations than group 3. No statistically significant differences between pairs of groups were detected for TAC concentrations. The principal component analysis (PCA) retained two principal components, (PC1 and PC2), explaining 60.1% of the observed variability of the inflammatory proteins and the antioxidant TAC. CONCLUSIONS: Increases in Serum SAA, Hp, and decreases in PON1 activity may indicate an active inflammatory state in infected cats (currently or recently infected).

Changes in salivary biomarkers of stress, inflammation, redox status, and muscle damage due to Streptococcus suis infection in pigs.

BACKGROUND: Streptococcus suis (S. suis) is a Gram-positive bacteria that infects pigs causing meningitis, arthritis, pneumonia, or endocarditis. This increases the mortality in pig farms deriving in severe economic losses. The use of saliva as a diagnostic fluid has various advantages compared to blood, especially in pigs. In this study, it was hypothesized that saliva could reflect changes in different biomarkers related to stress, inflammation, redox status, and muscle damage in pigs with S. suis infection and that changes in these biomarkers could be related to the severity of the disease. RESULTS: A total of 56 growing pigs from a farm were selected as infected pigs (n = 28) and healthy pigs (n = 28). Results showed increases in biomarkers related to stress (alpha-amylase and oxytocin), inflammation (haptoglobin, inter-alpha-trypsin inhibitor heavy chain 4 (ITIH4), total protein, S100A8-A9 and S100A12), redox status (advanced oxidation protein producs (AOPP)) and muscle damage (creatine kinase (CK), CK-MB, troponin I, lactate, aspartate aminotransferase, and lactate dehydrogenase). An increase in adenosine deaminase (ADA), procalcitonin, and aldolase in infected animals were also observed, as previously described. The grade of severity of the disease indicated a significant positive correlation with total protein concentrations, aspartate aminotransferase, aldolase, and AOPP. CONCLUSIONS: This report revealed that S. suis infection caused variations in analytes related to stress, inflammation, redox status, and muscle damage in the saliva of pigs and these can be considered potential biomarkers for this disease.

Divergences between serum C-reactive protein and ferritin concentrations in canine pyometra.

The main aim of this report was to investigate and compare the response of serum C-reactive protein (CRP) and ferritin, two positive acute phase proteins (APPs) which usually show an increase in inflammatory processes, in dogs with pyometra. For this purpose, two different studies were made. In the first one , both proteins were measured together in an APPs profile in 25 dogs with pyometra, 25 dogs with pancreatitis (as an example of a positive inflammatory control group), and in 25 healthy dogs. In the second study, to advance the knowledge of the changes and evolution of serum ferritin and CRP in dogs with pyometra after treatment, the concentrations of both APPs were analyzed in 30 dogs with pyometra at diagnosis and after ovariohysterectomy and in 10 clinically healthy female dogs before and after elective spaying. In both studies, bitches with pyometra showed significant increases in serum CRP, indicating an inflammatory condition, but not in serum ferritin despite being a moderate positive APP. This divergence between the dynamics of these APPs could be a useful tool for the suspicion of cases of canine pyometra.

Measurement of anti SARS-CoV-2 RBD IgG in saliva: validation of a highly sensitive assay and effects of the sampling collection method and correction by protein.

OBJECTIVES: To develop and evaluate a new highly sensitive assay to detect IgG anti-SARS-CoV-2 RBD in saliva samples. METHODS: A two-step sandwich type immunoassay based on the amplified luminescent proximity homogeneous technology was developed and an analytical validation was performed. As a part of this validation, the influence of factors, such as different sampling conditions (stimulated saliva and passive drool) and the correction of values by total protein content, in the ability of saliva to detect increases in antibodies after an immune stimulus and be an alternative to serum, was evaluated. For this purpose, paired samples of saliva and serum at different times after vaccination were used. RESULTS: Saliva concentrations were lower than serum, but both fluids showed similar kinetics, with higher correlations when saliva was obtained by passive flow and the results were not corrected by protein. CONCLUSIONS: The developed method showed a good analytical performance and can properly measure antibody concentrations in saliva of vaccinated individuals. However, saliva could have a lower sensitivity compared to serum at initial stages of the immune response and also when the antibody response decreased after a stimulus.

Measurement of procalcitonin in saliva of pigs: a pilot study.

BACKGROUND: Procalcitonin (PCT) is a widely used biomarker of sepsis in human medicine and can have potential applications in the veterinary field. This study aimed to explore whether PCT could be measured in the saliva of pigs and whether its concentration changes in sepsis. Therefore, a specific assay was developed and analytically validated, and changes in PCT concentration were evaluated in two conditions: a) in an experimental model of sepsis produced by the administration of lipopolysaccharide (LPS) to pigs (n = 5), that was compared with a model of non-septic inflammation induced by turpentine oil (n = 4), and b) in healthy piglets (n = 11) compared to piglets with meningitis (n = 20), a disease that usually involves sepsis and whose treatment often requires large amounts of antibiotics in farms. RESULTS: The assay showed coefficients of variation within the recommended limits and adequate linearity after serial sample dilutions. The method's detection limit was set at 68 µg/L, and the lower limit of quantification was 414 µg/L. In the LPS experiment, higher concentrations of PCT were found after 24 h in the animals injected with LPS (mean = 5790 µg/L) compared to those treated with turpentine oil (mean = 2127 µg/L, P = 0.045). Also, animals with meningitis had higher concentrations of PCT (mean = 21515 µg/L) than healthy pigs (mean = 6096 µg/L, P value < 0.0001). CONCLUSIONS: According to these results, this assay could be potentially used as a tool for the non-invasive detection of sepsis in pigs, which is currently a topic of high importance due to antibiotic use restriction.

A Proteomic Approach to Elucidate the Changes in Saliva and Serum Proteins of Pigs with Septic and Non-Septic Inflammation.

Sepsis is a systemic inflammatory response triggered by an infectious agent and is recognized by the World Health Organization as a global concern, since it is one of the major causes of severe illness in humans and animals. The study of the changes that can occur in saliva and serum in sepsis can contribute to a better understanding of the pathophysiological mechanisms involved in the process and also to discover potential biomarkers that can help in its diagnosis and monitoring. The objective of this study was to characterize the changes that occur in the salivary and serum proteome of pigs with experimentally-induced sepsis. The study included five pigs with sepsis induced by LPS administration and five pigs with non-septic inflammation induced by turpentine for comparative purposes. In saliva, there were eighteen salivary proteins differentially expressed in the sepsis condition and nine in non-septic inflammation. Among these, significant increments in aldolase A and serpin B12 only occurred in the sepsis model. Changes in aldolase A were validated in a larger population of pigs with sepsis due to Streptococcus suis infection. In serum, there were 30 proteins differentially expressed in sepsis group and 26 proteins in the non-septic group, and most of the proteins that changed in both groups were related to non-specific inflammation. In the saliva of the septic animals there were some specific pathways activated, such as the organonitrogen compound metabolic process and lipid transport, whereas, in the serum, one of the main activated pathways was the regulation of protein secretion. Overall, saliva and serum showed different proteome variations in response to septic inflammation and could provide complementary information about the pathophysiological mechanisms occurring in this condition. Additionally, salivary aldolase A could be a potential biomarker of sepsis in pigs that should be confirmed in a larger population.

Revealing the Changes in Saliva and Serum Proteins of Pigs with Meningitis Caused by Streptococcus Suis: A Proteomic Approach.

Meningitis due to Streptococcus suis causes high mortality and morbidity on pig farms and has increasing zoonotic potential worldwide. Saliva proteome analysis would potentially be useful in elucidating pathophysiological changes and mining for new biomarkers to diagnose and monitor S. suis infection. The objective of this study was to investigate the changes in the salivary and serum proteome profile of piglets with meningitis. The LC-MS/MS TMT proteomic approach was used to analyze saliva and serum samples from 20 male piglets: 10 with meningitis and 10 healthy. In saliva, 11 proteins had higher and 10 had lower relative abundance in piglets with meningitis. The proteins with the highest relative abundance were metavinculin (VCL) and desmocollin-2 (DSC2). Adenosine deaminase (ADA) was selected for validation using a spectrophotometric assay and demonstrated excellent performance in the differentiation between healthy and pigs with meningitis due to S. suis. In serum, the most protruding changes occurred for one SERPIN and haptoglobin (HP). In saliva and serum, the highest number of proteins with altered abundance were linked, via the enrichment analysis, with platelet and neutrophil pathways. Overall, meningitis caused by S. suis resulted in specific proteome changes in saliva and serum, reflecting different pathophysiological mechanisms, and marking new potential biomarkers for this infection.

Response of Muscle Damage Markers to an Accentuated Eccentric Training Protocol: Do Serum and Saliva Measurements Agree?

ABSTRACT: González-Hernández, JM, Jiménez-Reyes, P, Cerón, JJ, Tvarijonaviciute, A, Llorente-Canterano, FJ, Martínez-Aranda, LM, and García-Ramos, A. Response of muscle damage markers to an accentuated eccentric training protocol: do serum and saliva measurements agree? J Strength Cond Res 36(8): 2132-2138, 2022-This study aimed (a) to examine the acute and delayed responses of 3 muscle damage biomarkers: creatine kinase (CK), aspartate aminotransferase (AST), and lactate dehydrogenase (LDH) to an accentuated eccentric training protocol in serum, and (b) to explore the changes of these biomarkers in saliva and compare them with serum. Sixteen resistance-trained university students (10 men [age = 26.6 ± 4.8 years, full squat one repetition maximum [1RM] = 103.4 ± 14.4 kg] and 6 women [age = 22.7 ± 1.4 years, full squat estimated 1RM = 68.3 ± 10.5 kg]) completed an accentuated eccentric strength training protocol with the full squat exercise consisting of 8 sets of 10 repetitions against the 120% estimated 1RM load with 5 minutes of interset rest. The activity of muscle damage biomarkers (CK, AST, and LDH) was measured in serum and saliva before training (Pre), 24 hours after training (Post24), and 96 hours after training (Post96). In serum, lower values of the 3 muscle damage markers were observed at Pre compared to Post24 and Post96, whereas no significant differences were observed between Post24 and Post96 for any analyte. In saliva, there was a significant increase in men at Post96 compared with Pre in CK. The correlations between the measurements in serum and saliva ranged from trivial to small ( r = -0.034 to 0.212). These results suggest that the measurement of muscle damage markers in serum and saliva do not provide the same information in the conditions of our study.

Analytical validation of an automated assay for the measurement of adenosine deaminase (ADA) and its isoenzymes in saliva and a pilot evaluation of their changes in patients with SARS-CoV-2 infection.

OBJECTIVES: The aim of the present study was to validate a commercially available automated assay for the measurement of total adenosine deaminase (tADA) and its isoenzymes (ADA1 and ADA2) in saliva in a fast and accurate way, and evaluate the possible changes of these analytes in individuals with SARS-CoV-2 infection. METHODS: The validation, in addition to the evaluation of precision and accuracy, included the analysis of the effects of the main procedures that are currently being used for SARS-CoV-2 inactivation in saliva and a pilot study to evaluate the possible changes in salivary tADA and isoenzymes in individuals infected with SARS-CoV-2. RESULTS: The automated assay proved to be accurate and precise, with intra- and inter-assay coefficients of variation below 8.2%, linearity under dilution linear regression with R2 close to 1, and recovery percentage between 80 and 120% in all cases. This assay was affected when the sample is treated with heat or SDS for virus inactivation but tolerated Triton X-100 and NP-40. Individuals with SARS-CoV-2 infection (n=71) and who recovered from infection (n=11) had higher mean values of activity of tADA and its isoenzymes than healthy individuals (n=35). CONCLUSIONS: tADA and its isoenzymes ADA1 and ADA2 can be measured accurately and precisely in saliva samples in a rapid, economical, and reproducible way and can be analyzed after chemical inactivation with Triton X-100 and NP-40. Besides, the changes observed in tADA and isoenzymes in individuals with COVID-19 open the possibility of their potential use as non-invasive biomarkers in this disease.

Seroprevalence of Toxoplasma gondii in outdoor dogs and cats in Bangkok, Thailand.

The aim of this study was to estimate the seroprevalence and risk factors associated with Toxoplasma gondii exposure in dogs and cats from Bangkok, Thailand. Blood samples from 318 dogs and 321 cats were tested for T. gondii antibodies by modified agglutination test (cut-off 1:25). Additionally, 18 dogs and 20 cats were longitudinally sampled for T. gondii antibodies during the same study period, between June and July 2019. The overall seroprevalence in dogs and cats was 7.9% (25/318; 95% CI 4.9­10.8%) and 18.7% (95% CI 14.4­23.0%), respectively. For dogs, risk factors identified were being a mixed-breed animal and living totally outdoors, while increasing age was shown to be a risk factor for cats. Seroconversion was not detected and titres from positive animals remained constant over longitudinal study. The present study indicates that there is a prominent presence of T. gondii in urban and peri-urban areas of Bangkok, suggesting that outdoor dogs and cats should be considered as a possible risk factor for humans.

Salivary biomarkers in breast cancer: a cross-sectional study.

AIM: The objective was to evaluate the diagnostic value of salivary biomarkers in breast cancer. MATERIALS AND METHODS: A prospective study was carried out of 91 consecutive breast cancer patients and 60 controls without neoplastic disease. Demographic data were recorded, along with the Hospital Anxiety Depression (HAD), risk for development periodontal diseases questionnaire and Mini-Nutritional Assessment (MNA) scores, and the TNM classification and stage of the primary tumor. Unstimulated basal saliva samples were collected and stored at - 80 °C until analysis. RESULTS: The mean salivary CA125 concentration was 102.1 pg/ml in the control group and 267.6 pg/ml in the breast cancer group (p = 0.005). The soluble Fas (sFas) concentration in turn was 84.1 pg/ml and 145.9 pg/ml, respectively (p = 0.008). None of the biomarkers was related to questionnaire-assessed risk for development of periodontal diseases. The area under the ROC curve was 0.68 for CA125 (95% CI, 0.05-0.56) and 0.67 for sFas (95% CI, 0.08-0.55). CONCLUSIONS: The salivary biomarkers CA125 and sFas appear to be promising tools in the diagnosis of breast cancer.

Spectrophotometric assays for evaluation of Reactive Oxygen Species (ROS) in serum: general concepts and applications in dogs and humans.

Reactive oxygen species (ROS) are reactive compounds derived from oxygen. In biological systems, an excessive amount of ROS can cause oxidative damage to biological macromolecules being involved in different diseases. Several assays have been developed in the last 30 years for ROS evaluation. The objective of this article will be to provide an update about the spectrophotometric methods currently used in the assessment of ROS in serum. The chemical basis of four different techniques will be reviewed, and examples of their possible applications will be provided. A particular emphasis about the practical applications of these assays in the dog will be made, but selected information about their use in humans will also be presented for comparative purposes, following a One-Health approach. The information about the spectrophotometric assays presented in this paper should be interpreted with caution once limited information about them is available yet, and further studies should be performed to clarify what they measure and their clinical application. Ideally, when applied to evaluate a sample's oxidative status, they should be incorporated in a panel of analytes where other oxidants, antioxidants, and biomarkers of inflammation were also included.

Changes in salivary biomarkers of oxidative status in calves at weaning and grouping.

BACKGROUND: Saliva is being increasingly used as a sample for measuring biomarkers in several species and shows a high potential of use to detect and monitor stress. The weaning and grouping in dairy calves are a particularly stressful time. Therefore, the objectives of this study were to evaluate a panel of antioxidant and oxidant biomarkers in the saliva of calves on the day of weaning (W0), 2 days after weaning or milk withdrawal (W + 2), and 4 days after grouping (G + 4). In addition, to verify if cortisol and oxytocin concentrations are related to the biomarkers measured. RESULTS: Salivary cupric reducing antioxidant capacity (CUPRAC), ferric reducing ability of saliva (FRAS), Trolox equivalent antioxidant capacity (TEAC), advanced oxidation protein products (AOPP), and ferrous oxidation-xylenol orange (FOX) were significantly higher (P < 0.02) 4 days after grouping than the day of weaning and 2 days after. The increases were 50 and 54% for CUPRAC, 93 and 116% for FRAS, 117 and 135% for TEAC, 22 and 49% for AOPP and 10 and 5% for FOX in comparison with weaning and 2 days after, respectively. In addition, oxytocin and cortisol showed significant negative and positive correlations (P < 0.05) respectively with the biomarkers of oxidative status. CONCLUSIONS: Our results showed that calves after grouping show increases in antioxidants and oxidants concentrations, indicating that a balance between these molecules has been tried to maintain during this stressful situation. The dynamic changes of biomarkers of oxidative status should be explored and characterised in other stressful conditions.

Changes of adenosine deaminase activity in serum and saliva around parturition in sows with and without postpartum dysgalactia syndrome.

BACKGROUND: Postpartum dysgalactia syndrome (PDS) is associated with a significantly higher activation of the inflammatory and stress response at parturition than in the healthy sow. Therefore, reliable and possibly non-invasive biomarkers for substantial increases of inflammation are searched to support the PDS diagnosis. This report studies the possible changes of the inflammatory marker enzyme adenosine deaminase (ADA) in serum and saliva of 38 PDS positive sows (PDS+) and 38 healthy sows (PDS-). Sampling was performed every 24 h from 60 h before to 36 h after parturition. Isoenzyme 1 (ADA1) and isoenzyme 2 (ADA2), as well as total ADA (tADA), were measured and their statistical association with several serum and saliva biomarkers of inflammation and stress was investigated. RESULTS: Compared to a baseline (60 to 36h prepartum), salivary activities of ADA1, ADA2 and tADA increased significantly over time in both PDS+ and PDS- sows, reaching their peaks after parturition. In serum from PDS- sows, no changes were observed over time in either ADA1, ADA2 or tADA. In PDS+ sows, serum ADA2 activity decreased temporarily after parturition followed by a significant increase compared to baseline. ADA1, ADA2 and tADA were all significantly associated with several inflammatory biomarkers and ADA1 in serum was associated with serum cortisol. Although serum activity was higher in PDS+ than in PDS- sows, the differences were not statistically significant. Further, no difference was noted between the groups in the analyses of saliva. CONCLUSIONS: Salivary ADA1 and ADA2 increased in all sows after parturition, potentially as a response to the postpartum inflammation. However, no difference in the activity of ADA1, ADA2 and tADA were found between PDS+ and PDS- sows indicating inability to diagnose PDS under the conditions described in this report.

Oxytocin in bovine saliva: validation of two assays and changes in parturition and at weaning.

BACKGROUND: The possible use of oxytocin in saliva as an indicator of positive emotions in bovine species has been poorly investigated. In the present study, two new assays (one using a monoclonal antibody and the other using a polyclonal antibody) for the measurement of oxytocin in bovine saliva were developed and validated. Also, the changes in oxytocin in saliva were explored in two different situations. One was around parturition, and for this purpose, saliva samples from 13 cows were collected at three different times: 7 days before the parturition, the day of parturition and 7 days after the parturition. The second situation was weaning and grouping of calves, and for this purpose, saliva from 25 calves was collected at three different times: 1 day before weaning, 2 days after weaning or milk withdrawal and 4 days after grouping calves. RESULTS: In cows, oxytocin concentrations showed an increase on the day of parturition with both assays, while in calves, oxytocin concentrations showed a decrease 4 days after the grouping. CONCLUSIONS: The assays validated in this report could be used for the measurement of oxytocin in bovine saliva and detect changes in this analyte that can occur in different physiological or productive situations such as parturition and weaning.

Resistance Training to Failure vs. Not to Failure: Acute and Delayed Markers of Mechanical, Neuromuscular, and Biochemical Fatigue.

ABSTRACT: González-Hernández, JM, García-Ramos, A, Colomer-Poveda, D, Tvarijonaviciute, A, Cerón, J, Jiménez-Reyes, P, and Márquez, G. Resistance training to failure vs. not to failure: acute and delayed markers of mechanical, neuromuscular, and biochemical fatigue. J Strength Cond Res 35(4): 886-893, 2021-This study aimed to compare acute and delayed markers of mechanical, neuromuscular, and biochemical fatigue between resistance training sessions leading to or not to failure. Twelve resistance-trained men completed 2 sessions that consisted of 6 sets of the full-squat exercise performed against the 10 repetitions maximum load. In a randomized order, in one session the sets were performed to failure and in the other session the sets were not performed to failure (5 repetitions per set). Mechanical fatigue was quantified through the recording of the mean velocity during all repetitions. The neuromuscular function of the knee extensors was assessed through a maximal voluntary contraction and the twitch interpolation technique before training, immediately after each set, and 1, 24, and 48 hours post-training. Serum creatine kinase (CK) and aspartate aminotransferase (AST) were measured before training and 1, 24, and 48 hours post-training to infer muscle damage. Alpha was set at a level of 0.05. A higher velocity loss between sets was observed during the failure protocol (-21.7%) compared with the nonfailure protocol (-3.5%). The markers of peripheral fatigue were generally higher and long lasting for the failure protocol. However, the central fatigue assessed by the voluntary activation was comparable for both protocols and remained depressed up to 48 hours post-training. The concentrations of CK and AST were higher after the failure protocol revealing higher muscle damage compared with the nonfailure protocol. These results support the nonfailure protocol to reduce peripheral fatigue and muscle damage, whereas the central fatigue does not seem to be affected by the set configuration.

Changes of inflammatory and oxidative stress biomarkers in dogs with different stages of heart failure.

BACKGROUND: Heart failure (HF) is associated with changes in inflammatory and oxidative stress biomarkers. This study aimed to evaluate the changes of a panel of inflammatory and oxidative stress biomarkers in dogs with different stages of HF and its relation with the severity of the disease and echocardiographic changes. A total of 29 dogs with HF as a result of myxomatous mitral valve degeneration or dilated cardiomyopathy were included and classified as stage-A (healthy), B (asymptomatic dogs), C (symptomatic dogs) and D (dogs with end-stage HF) according to the ACVIM staging system. In these dogs an ecnhocardiographic examination was performed and cytokines, and inflammatory and oxidative stress markers were evaluated in serum. RESULTS: KC-like was significantly increased in dogs of stage-C (P < 0.01) and -D (P < 0.05) compared with stage-A and -B. Stage-D dogs showed significantly higher serum CRP and Hp (P < 0.05) but lower serum antioxidant capacity (PON1, TEAC, CUPRAC, and thiol) compared to stage-A and -B (P < 0.05). After the treatment, serum levels of CRP, Hp and KC-like decreased and serum antioxidant levels increased compared to their pre-treatment values. Left ventricular dimension and LA/Ao ratio correlated positively with CRP, MCP-1, and KC-like but negatively with PON1, GM-CSF, IL-7 and antioxidant biomarkers (P < 0.01). CONCLUSION: Our results showed that dogs with advanced HF show increases in positive acute-phase proteins and selected inflammatory cytokines such as KC-like, and decreases in antioxidant biomarkers, indicating that inflammation and oxidative stress act as collaborative partners in the pathogenesis of HF. Some of these biomarkers of inflammation and oxidative stress could have the potential to be biomarkers to monitor the severity of the disease and the effect of treatment.