Presence of SARS-CoV-2-specific T cells before vaccination in the Mexican population.

The immune response to SARS-CoV-2 has been extensively studied following the pandemic outbreak in 2020; however, the presence of specific T cells against SARS-CoV-2 before vaccination has not been evaluated in Mexico. In this study, we estimated the frequency of T CD4+ and T CD8+ cells that exhibit a specific response to S (spike) and N (nucleocapsid) proteins in a Mexican population. We collected 78 peripheral blood samples from unvaccinated subjects and the presence of antibodies against spike (RBD) and N protein was determined. PBMCs (peripheral blood mononuclear cells) were isolated and stimulated with a pool of S or N protein peptides (Wuhan-Hu-1 strain). IL-1ß, IL-4, IL-6, IL-10, IL-2, IL-8, TNF-α, IFN-γ, and GM-CSF levels were quantified in the supernatant of the activated cells, and the cells were stained to assess the activation and memory phenotypes. Differential activation frequency dependent upon serological status was observed in CD4+ cells, but not in CD8+ cells. The predominantly activated population was the central memory T CD4+ cells. Only 10% of the population exhibited the same phenotype with respect to the response to nucleocapsid peptides. The cytokine profile differed between the S and N responses. S peptides induced a more proinflammatory response compared with the N peptides. In conclusion, in a Mexican cohort before vaccination, there was a significant response to the S and N SARS-CoV-2 proteins resulting from previous infections with seasonal coronaviruses or previous undetected exposure to SARS-CoV-2.

Association between Gut Microbiota and Inflammation: Mediation Analysis Using Waist Circumference.

Chronic low-grade inflammation (CLI) is implicated in the development of multiple metabolic diseases. The gut microbiota (GM) activates different signaling pathways and induces phenotypic changes, offering an exciting opportunity to treat CLI. We evaluated the mediation of waist circumference on the association of GM with serum cytokines. In this cross-sectional study of 331 children, we measured 5 gut bacterial species, namely, Lactobacillus (L.) casei, L. paracasei, L. reuteri, Staphylococcus (S.) aureus, and Akkermansia (A.) muciniphila, as well as anthropometry, serum cytokines, and other covariates. We evaluated adjusted regression models, path analysis, and structural equation modeling to obtain path coefficients (PCs) for direct, indirect (waist circumference-mediated), and total effects. We found that L. paracasei was directly associated with lower interleukin-10 (IL-10) levels (PC = -173.5 pg/mL). We also observed indirect associations between S. aureus with lower adiponectin levels (PC = -0.1 µg/mL and -0.09 µg/mL). Finally, A. muciniphila was indirectly associated with higher adiponectin levels (PC = 0.1 µg/mL). Our findings suggest the importance of considering the GM composition and waist circumference when evaluating inflammatory-related factors, providing a basis for future research to identify potential strategies to intervene in inflammatory processes and prevent metabolic diseases in childhood. [Figure: see text].

Interaction between Akkermansia muciniphila and Diet Is Associated with Proinflammatory Index in School-Aged Children.

BACKGROUND: Imbalance in the intestinal microbiota can lead to chronic low-grade inflammation. Diet may influence this association. In this study, we aimed to evaluate the interaction between Akkermansia muciniphila (A. muciniphila) and dietary patterns using a proinflammatory index. METHODS: We conducted a cross-sectional study with school-aged children. We quantified the relative abundance (RA) of A. muciniphila in feces using a polymerase chain reaction. We collected dietary information through employing a food frequency questionnaire and generated dietary patterns using principal component analysis. We generated a proinflammatory index from serum levels of interleukin-6, interleukin-10, tumor necrosis factor alpha, and adiponectin validated by receptor operating characteristic curves. We evaluated the association between A. muciniphila and the proinflammatory index using logistic regression, including an interaction term with dietary patterns. RESULTS: We found that children with a low RA of A. muciniphila and a high intake of simple carbohydrates and saturated fats had increased odds of being high on the proinflammatory index. However, when the consumption of this dietary pattern is low, children with a low RA of A. muciniphila had decreased odds of being high on the proinflammatory index. CONCLUSIONS: Our results suggest that the simultaneous presence of A. muciniphila and diet have a more significant impact on the presence of being high on the proinflammatory index compared to both factors separately.

Mediation Analysis of Waist Circumference in the Association of Gut Microbiota with Insulin Resistance in Children.

BACKGROUND: Persistent gut microbiota (GM) imbalance has been associated with metabolic disease development. This study evaluated the mediating role of waist circumference in the association between GM and insulin resistance (IR) in children. METHODS: This cross-sectional study included 533 children aged between 6 and 12. The anthropometry, metabolic markers, and relative abundance (RA) of five intestinal bacterial species were measured. Path coefficients were estimated using path analysis to assess direct, indirect (mediated by waist circumference), and total effects on the association between GM and IR. RESULTS: The results indicated a positive association mediated by waist circumference between the medium and high RA of S. aureus with homeostatic model assessments for insulin resistance (HOMA-IR) and for insulin resistance adiponectin-corrected (HOMA-AD). We found a negative association mediated by waist circumference between the low and medium RA of A. muciniphila and HOMA-IR and HOMA-AD. Finally, when we evaluated the joint effect of S. aureus, L. casei, and A. muciniphila, we found a waist circumference-mediated negative association with HOMA-IR and HOMA-AD. CONCLUSIONS: Waist circumference is a crucial mediator in the association between S. aureus and A. muciniphila RA and changes in HOMA-IR and HOMA-AD scores in children.

Association of Gut Microbiota with Dietary-dependent Childhood Obesity.

AIM: To evaluate the taxonomic profile of the gut microbiota using metagenomics and the association with diet-dependent childhood obesity. METHODS: A cross-sectional study of a subsample of 46 children was conducted. The children were classified as normal-weight, overweight, and obese according to their age and sex and the World Health Organization (WHO) guidelines. Dietary patterns were determined through principal component analysis. The profile of the human gut microbiota was determined by bioinformatic analysis using whole metagenome shotgun sequencing. The association of gut microbiota and z-BMI, waist circumference and hip circumference, and the possible modifying effect of diet were analyzed using multiple regression models. RESULTS: Children with an abundance of Holdemania spp. and high protein and complex carbohydrate consumption had a lower z-BMI (ß -19.06, p = 0.011), waist circumference (ß -171.92, p = 0.003), and hip circumference (ß -157.57, p = 0.004). In contrast, observed a positive association between Coprococcus catus and the low intake of this dietary pattern with hip circumference (ß 147.87, p = 0.025). Furthermore, the presence of Bilophila spp. and Paraprevotella xylaniphila with high saturated fat and simple carbohydrate consumption we observed a positive association between z-BMI (ß 47.5, p = 0.002), hip circumference (ß 44.54, p = 0.025), and waist circumference (ß 44.34, p = 0.004). CONCLUSION: We suggest that the synergism between diet and the profile of children's gut microbiota can be a factor that could be associated with the development of obesity and its complications in childhood.

Severe Quantitative Scale of Acanthosis Nigricans in Neck is Associated with Abdominal Obesity, HOMA-IR, and Hyperlipidemia in Obese Children from Mexico City: A Cross-Sectional Study.

Background: Acanthosis nigricans (AN) is a clinical sign that commonly occurs in obesity; however, its specificity and sensitivity have been controversial. It is unknown if AN severity degree can be a useful marker for cardiometabolic disorders screening. We suggest that the stratified analysis of AN severity degree in neck by Burke's scale could be a useful tool in the screening of cardiometabolic alterations in obese children. Objective: The aim of this study was the association of AN severity degree in neck by Burke's scale with anthropometric, biochemical, and inflammatory parameters in obese school-age children from Mexico City. Methods: A cross-sectional study was conducted, including 95 obese school-age children stratified by AN severity degree in neck by Burke's scale. Anthropometric and fasting biochemical measurements were determined. Variables were compared by x 2 test for frequencies and one-way ANOVA with Bonferroni posttest for continuous variables. Linear regression analysis adjusted by gender, BMI, and age was performed to evaluate the association between AN severity degree and cardiometabolic alterations. Statistical significance was set at p < 0.05. Results: As AN severity degree in neck by Burke's scale increased, diastolic blood pressure (p=0.001) and triglycerides (p=0.02) significantly increased and adiponectin significantly decreased (p=0.02). Positive associations between grade 3 AN and waist circumference, HOMA-IR, triglycerides, total cholesterol, and LDL cholesterol were observed. Conclusion: Our findings could be used to identify an easier clinical tool to prevent obesity progression and its complications in pediatrics. There are no similar studies.

High Relative Abundance of Staphylococcus aureus and Serum Cytokines Are Associated with Cardiometabolic Abnormalities in Children.

Background: The alteration in the composition of the gut microbiota has been associated with an increased risk of developing cardiovascular and metabolic diseases. The present study evaluated the association between the relative abundance (RA) of intestinal Staphylococcus aureus and the inflammatory response with cardiometabolic alterations in children. Methods: This cross-sectional study included 1142 children (age 6-12 years), which were classified by degree of adiposity. Anthropometry, cardiometabolic markers, and RA of intestinal S. aureus were measured. Cytokine concentrations were available in 626 children. Path coefficients (PC) were estimated by path analysis. Results: RA of S. aureus was positively associated with cholesterol PC = 24.98 (95% CI 10.76 to 39.21) and negatively with triglycerides PC = -13.10 (95% CI -22.73 to -3.48). Body mass index (BMI) Z-scores had significant mediation effects on the association between RA of S. aureus with waist circumference PC = 2.87 (95% CI 0.58 to 5.16), triglycerides PC = 6.63 (95% CI 1.29 to 11.98), low-density lipoproteins (LDL) PC = 1.73 (95% CI 0.27 to 3.18), and high-density lipoproteins PC = -1.20 (95% CI -2.19 to -0.22). Interleukin 6 (IL-6) was negatively associated with glucose PC = -3.01 (95% CI -5.85 to -0.17) and LDL PC = -8.65 (95% CI -16.54 to -0.77), and interleukin 10 (IL-10) was positively associated with glucose PC = 3.37 (95% CI 0.47 to 6.26). Conclusions: It is suggested that the RA of S. aureus, IL-6, and IL-10 are associated with cardiometabolic alterations in children, where BMI Z-scores have an important mediating effect for the development of these.

Alterations of the Gut Microbiome Associated to Methane Metabolism in Mexican Children with Obesity.

Gut microbiota is associated with the development of metabolic disorders. To study its association with childhood obesity, we performed a cross-sectional study with 46 children (6-12 years old). We collected fecal samples, food-frequency questionnaires (FFQs), and anthropometric measurements. Shotgun metagenomics were used to obtain the microbial taxonomic diversity and metabolic potential. We identified two dietary profiles characterized by complex carbohydrates and proteins (pattern 1) and saturated fat and simple carbohydrates (pattern 2). We classified each participant into normal weight (NW) or overweight and obese (OWOB) using their body mass index (BMI) z-score. The ratio of Firmicutes/Bacteroidetes and alpha diversity were not different between the BMI groups. Genera contributing to beta diversity between NW and OWOB groups included Bacteroides rodentium, B. intestinalis, B. eggerthii, Methanobrevibacter smithii, Eubacterium sp., and Roseburia sp. B. rodentium was associated with lower BMI and dietary pattern 1 intake. Eubacterium sp. and Roseburia sp. were associated with BMI increments and high consumption of dietary pattern 2. Methane and energy metabolism were found enriched in under-represented KEGG pathways of NW group compared to OWOB. Complex dietary and microbiome interaction leads to metabolic differences during childhood, which should be elucidated to prevent metabolic diseases in adolescence and adulthood.

Lactobacillus paracasei as a protective factor of obesity induced by an unhealthy diet in children.

This study examined the association between intestinal lactobacilli and obesity dependent on dietary patterns in children. A cross-sectional study was conducted including 1111 children, 6-12 years old. Obesity was determined according to the WHO cut-off points. Diet information from a Food Frequency Questionnaire identified three dietary patterns. Lactobacillus sp. were determined by a real-time polymerase chain reaction (PCR). The consumption of complex carbohydrates and a high abundance of L. paracasei were associated with a lower risk of obesity (0.35, Confidence Interval 95% 0.19-0.65). The same happened with a medium consumption of fats and a medium abundance of L. paracasei (0.43, CI95% 0.24-0.78). In contrast, an increased risk of obesity is observed with a medium and high consumption of simple carbohydrates (2.37, CI95% 1.29-4.34 and 2.52, CI95% 1.36-4.66, respectively, p-trend<0.05), and low consumption of complex carbohydrates (2.49, CI95% 1.35-4.58), in the presence of a high relative abundance of L. reuteri. A high relative abundance of L. paracasei decreased the risk of obesity, even when high-fat and simple carbohydrate diets were consumed; while a high relative abundance of L. reuteri was associated with a greater possibility of obesity with these types of diets. Our results provide evidence of diet implication in metabolism regulators like lactobacilli. This is helpful in strategies development to promote healthy diets during early stages of life.