Analysis of SIRT1 genetic variants in young Mexican individuals: relationships with overweight and obesity

The high prevalence of obesity in Mexico starting from the early stages of life is concerning and represents a major public health problem. Genetic association studies have reported that single nucleotide variants (SNVs) in SIRT1, an NAD+-dependent deacetylase that plays an important role in the regulation of metabolic cellular functions, are associated with multiple metabolic disorders and the risk of obesity. In the present study, we analyzed the effect that the SNVs rs1467568 and rs7895833 of the SIRT1 gene may have on cardiometabolic risk factors in a young adult population from Mexico. A cross-sectional study was carried out with young adults between the ages of 18 and 25 who had a body mass index (BMI) greater than 18.5 kg/m2. This study included 1122 young adults who were classified into the normal weight (n = 731), overweight group (n = 277), and obesity group (n = 114) according to BMI of whom 405 and 404 volunteers were genotyped for rs1467568 and rs7895833 respectively using TaqMan probes through allelic discrimination assays. We found that the male sex carrying the G allele of rs7895833 had slightly lower BMI levels (p = 0.009). Furthermore, subjects carrying rs1467568 (G allele) showed a 34% lower probability of presenting with hyperbetalipoproteinemia where female carrying rs1467568 had lower levels of total cholesterol (p = 0.030), triglycerides (p = 0.026) and LDL cholesterol (p = 0.013). In conclusion, these findings suggest that the presence of both SNVs could have a non-risk effect against dyslipidemia in the Mexican population.

Glycemia and associated factors in a pediatric population in Mexico

Aims

In this study, we evaluated the association of sociodemographic, lifestyle and cardiometabolic factors with blood glucose levels in children and adolescents in Mexico.

Methods

An analytical cross-sectional study of 642 children and adolescents aged 6 to 19 years from different educational centers located in municipalities of the state of San Luis Potosí, Mexico, was carried out. Pearson χ2 and Spearman correlation tests and multiple linear regression models were used to evaluate the associations of the variables with glycemia.

Results

The prevalence of prediabetes was 8.0% in both sexes. Male participants were more likely to develop hyperglycemia than female participants (OR 2.7, 95% CI: 1.5-5.0). The variables associated with glucose levels were male sex, high socioeconomic status, inadequate diet, high blood pressure, and increased total cholesterol, LDL cholesterol, and triglycerides, which also explained up to 15.6% (p < 0.05) of the variability in glucose concentrations.

Conclusion

The detection of sociodemographic, lifestyle and cardiometabolic factors in children and adolescents will contribute to the implementation of prevention strategies for cardiometabolic diseases, among which prediabetes is common.

Agave fructans enhance the effects of fermented milk products on obesity biomarkers: a randomised trial

Dysbiosis has been implicated in childhood obesity. Oral intake of fermented milk containing Lacticaseibacillus casei strain Shirota preserves gut microbiota (GM) diversity in children and adults. This study was a double-blind trial involving 37 overweight or obese children aged 6-10 years. Children were followed over a 6-week intervention period in which they received different fermented milk products containing L. casei Shirota: 10 in the first group received just L. casei Shirota; 13 received L. casei Shirota with 3 g/day of inulin (L. casei+inulin); and 14 received L. casei Shirota with 3 g/day of fructans from Agave salmiana (L. casei+fructans). Principal component analysis showed the relationship between microbial abundance, GM metabolites, and other obesity-related markers. Supplementation with probiotics and synbiotics improved the HDL-cholesterol levels of overweight and obese children, although no changes in body composition were detected. We observed an increase in butyrate or propionate concentrations in the L. casei+fructans group compared to the end of the intervention (P<0.03). A diminished level of ANGPTL4 within the L. casei+fructans group (P=0.04) was also found, but no differences when lipopolysaccharide-binding protein was evaluated. The FFAR2+ cell frequency decreased between baseline and at the end of 6-week intervention in L. casei+inulin (P=0.02) and L. casei+fructans groups (P=0.04). In contrast, the percentage of CD14+FFAR3+ frequency increased in the same groups (P=0.04). The L. casei Shirota with inulin or fructans modulates GM, which improves the lipid profile and changes at a molecular level, such as expression of FFAR3 and FFAR2, ANGPTL4, propionate, and butyrate. It, therefore, could be considered an interesting therapeutic possibility for treating childhood overweight and obesity. The study was registered at ClinicalTrials.gov (ID: NCT05423015).

Uricaemia and associated health determinants in a paediatric population in Mexico

BACKGROUND AND AIM

Uric acid (UA) is a product of the catabolism of purines, and its increase in blood may be related to the development of cardiometabolic diseases. Whether UA is the result or causal determinant of the appearance of risk factors for cardiometabolic disease is not yet known. UA levels among the young student population in San Luis Potosi have increased in recent years, which may be indicative of a serious future public health concern. Therefore, the objective of this study was to evaluate the association of sociodemographic, lifestyle and cardiometabolic determinants with UA levels in children and adolescents in San Luis Potosí.

METHODS AND RESULTS

A total of 730 students (54.1% female and 45.9% male, 6-19 years old) participated in the study. The subjects attended one of five public schools located in San Luis Potosí. Venous blood samples were collected, blood serum was separated by centrifugation, and UA concentrations were measured with an automated analytical platform. UA was associated with most of the independent variables studied. It presented a positive correlation with body mass index (r = 0.363, p < 0.01). Male sex, socioeconomic status, total screen time, exercise, adequate sleep, systolic blood pressure, total cholesterol, and high-density lipoprotein cholesterol explained 23%-39% (p < 0.001) of the variability of plasma concentrations of UA in children and adolescents.

CONCLUSION

Early detection of these determinants will prevent future diseases. Moreover, it will help with the implementation of preventive strategies that could improve the health of this population.

Expression of NAT2 in immune system cells and the relation of NAT2 gene polymorphisms in the anti-tuberculosis therapy in Mexican mestizo population

Arylamine N-acetyltransferase 2 (NAT2) metabolizes isoniazid (INH) and Single Nucleotide Polymorphisms (SNP) responsible for its activity has been reported. The aim of this study in the Mexican mestizo population was to evaluate NAT2 expression at the protein level in immune cells, as well as the distribution and frequency of six NAT2 SNPs and their association with anti-TB therapy, by measuring the plasma levels of INH and Acetyl-INH (AcINH). We performed genotyping assays of NAT2 SNPs in 40 TB patients and 121 healthy volunteers by real-time PCR. A method for detecting NAT2 in immune cells using flow cytometry was developed. Plasma concentrations of INH and AcINH were obtained by HPLC in TB patients and the Metabolic Ratio (MR) was calculated. The phenotypes obtained in the healthy volunteers were as follows; 18.87 % of subjects had the rapid acetylator phenotype, 45.45 % had the intermediate phenotype and 39.66 % exhibited the slow acetylator phenotype. In the TB patient group, 35 % of patients had the rapid acetylator phenotype, 32.5 % were intermediate and 32.5 % showed the slow acetylator phenotype. A higher expression level of NAT2 in innate immune cells from TB patients compared to those from healthy volunteers was detected (P < 0.013). In TB patients the MR showed a bimodal distribution with an antimode of 0.7, which was used as a threshold value for acetylator classification. A high correspondence between the rapid and slow acetylator phenotype with MR was demonstrated. In conclusion, the 282C>T, 341T>C, 481C>T, 590G>A, 803A>G, 857G>A SNPs of NAT2 gene provides accurate for prediction of the acetylator phenotype in Mexican mestizo population. A statistical difference was found in frequency of rapid metabolizer phenotype, which was higher in TB patients. In addition, the expression of NAT2 protein in immune cells can lead to further studies related to its functional role in the innate immune response against M. tuberculosis and other xenobiotics metabolized by this enzyme.

Arsenic and fluoride co-exposure affects the expression of apoptotic and inflammatory genes and proteins in mononuclear cells from children

Humans may be exposed to arsenic (As) and fluoride (F) through water consumption. However, the interaction between these two elements and gene expression in apoptosis or inflammatory processes in children has not been thoroughly investigated. Herein, the expression of cIAP-1, XIAP, TNF-α, ENA-78, survivin, CD25, and CD40 was evaluated by RT-PCR. Additionally, the surface expression of CD25, CD40, and CD40L on peripheral blood mononuclear cells was analyzed by flow cytometry, and TNF-α was measured by Western blotting. This study examined 72 children aged 6-12 years who were chronically exposed to As (154.2μg/L) and F (5.3mg/L) in drinking water and in food cooked with the same water. The urine concentrations of As (6.9-122.4μg/L) were positively correlated with the urine concentrations of F (1.0-8.8mg/L) (r(2)=0.413, p<0.0001). The CD25 gene expression levels and urine concentrations of As and F were negatively correlated, though the CD40 expression levels were negatively correlated only with the As concentration. Age and height influenced the expression of cIAP-1, whereas XIAP expression was correlated only with age. Additionally, there was a lower percentage of CD25- and CD40-positive cells in the group of 6- to 8-year-old children exposed to the highest concentrations of both As and F when compared to the 9- to 12-year-old group (CD25: 0.7±0.8 vs. 1.1±0.9, p<0.0014; CD40: 16.0±7.0 vs. 21.8±5.8, p<0.0003). PHA-stimulated lymphocytes did not show any changes in the induction of CD25, CD69, or CD95. In summary, high concentrations of As and F alter the expression patterns of CD25 and CD40 at both the genetic and protein levels. These changes could decrease immune responses in children exposed to As and F.

Dysregulated miR-155 expression in peripheral blood mononuclear cells from patients with type 2 diabetes

MicroRNAs (miRNAs) are involved in gene regulation of several physiological processes. Alterations in the concentrations of miRNAs may result in cancer and autoimmune diseases. In cells of the immune system, miRNA expression is regulated by several cytokines and this expression is related to the inflammatory process. In the present work we evaluated miR-155 and miR-146a levels in peripheral blood mononuclear cells (PBMC) from patients with type 2 diabetes (T2D).We analysed the expression of miRNAs in PBMC from T2D patients (n=20) and control subjects (n=20) using real-time PCR. The quantity of IL-1β and IL-6 in culture supernatants was measured by ELISA.The basal expression of miR-155 and miR-146a in patients with T2D was decreased compared to control subjects and associated with age, gender and metabolic control but not with the therapeutic treatment used. We found significant correlations between the basal expression of miR-155 and miR-146a with HbA1c, Glucose and BMI, as well as of miR-155 expression stimulated by LPS with the values of TG, HbA1c, Glucose and BMI. Additionally, we detected an altered distribution of miR-155 and miR-146a expression related with HbA1c, glucose and BMI using the analysis of a three dimensional association of variables in the group of T2D patients.Downregulated levels of miR-155 could play an important role in the pathogenesis of T2D due to their relationship with metabolic control.

Regulatory T Cells in children with intestinal parasite infection

Chronic intestinal parasite infection can induce both persistent immune activation and defective responsiveness of T cells. This study aimed to assess the number and function of T regulatory (Treg) cells in children with intestinal parasite infection. We have studied the peripheral blood from 93 children, 53 of them parasitized with protozoa, helminths, or both; the remainder were non parasitized, healthy controls. The number and function of CD4(+) CD25(high) and CD4(+) Foxp3(+) cells were similar in parasitized and control children. In contrast, there was a significant increase in the levels of CD3(+) CD69(+), CD4(+) CTLA-4(+), and CD8(+) CD28(-) T cells in helminth infected children. Moreover, some of these patients showed a diminished response to CD3/CD28 stimulation in comparison with the control children. Our data strongly suggest that whilst Treg cells are not affected by intestinal parasite infection, CD3(+) CD69(+), CD4(+) CTLA-4(+) and CD8(+) CD28(-) lymphocytes may play an important, but as yet undetermined role in the diminished immune competence observed in parasitized children.

Effect of arsenic on regulatory T cells

INTRODUCTION

Arsenic (As) affects the function and survival of lymphocytes, and some arsenic compounds exert a relevant antineoplastic effect. We have explored the effect of As on T regulatory cells.

RESULTS AND DISCUSSION

In vitro experiments with peripheral blood mononuclear cells from healthy subjects showed that low concentrations of As tended to increase the number of natural T regulatory (nTreg) lymphocytes, whereas concentrations >5.0 muM had an opposite effect. Furthermore, rats exposed to As showed redistribution of nTreg cells, and As administration to rats with experimental allergic encephalomyelitis increased the levels of nTreg cells in spleen and diminished the severity of this condition. On the other hand, in 47 apparently healthy subjects chronically exposed to As, we found significant inverse correlation between urinary As levels and the number and function of nTreg lymphocytes. Although most of these individuals showed enhanced levels of apoptotic lymphocytes in peripheral blood, with a diminution of mitochondrial membrane potential, no significant correlation between these parameters and urinary As was detected.

CONCLUSION

Our data indicate that As seems to have a relevant and complex effect on nTreg cells.

Expression and function of IL-10R in mononuclear cells from patients with systemic lupus erythematosus

OBJECTIVE

To assess the expression and function of the receptor for interleukin-10 (IL-10R) in immune cells from patients with systemic lupus erythematosus (SLE).

METHODS

We assessed the expression and function of IL-10R in peripheral blood mononuclear cells (PBMCs) from 19 SLE patients and 15 healthy controls. The expression of IL-10R was assessed by flow cytometry, and the function of this receptor was determined by analysing both the activation of Jak-1, Tyk-2, Stat-1, and Stat-3 (Western blot) and the induction of gene expression (cDNA array test of 242 genes of cytokines, apoptosis and intracellular signalling) upon stimulation with IL-10.

RESULTS

We found similar levels of IL-10R expression in SLE patients and controls. In addition, variable levels of Jak-1, Tyk-2, Stat-1, and Stat-3 activation were induced by IL-10 in PBMCs from SLE patients and controls, with no significant differences in protein phosphorylation or kinetics of activation. However, clear-cut differences in the gene expression induced through IL-10R were observed in SLE patients and controls, mainly in the genes involved in apoptosis and those encoding for cytokines and their receptors.

CONCLUSIONS

Our data suggest that despite normal levels of IL-10R expression, and an apparent lack of abnormalities in the intracellular signals induced through this receptor, immune cells from SLE patients exhibit an aberrant pattern of gene expression induced through the IL-10R.

Co-stimulatory signals increase the reactivity of gammadelta T cells towards mycobacterial antigens

Although it has been shown that gammadelta T lymphocytes are able to react with different cell-associated or soluble antigens, the immune repertoire of these cells appears to be skewed to the recognition of mycobacterial antigens. We have studied the number and reactivity of gammadelta T cells towards several mycobacterial antigens in patients with tuberculosis and leprosy, as well as their healthy contacts and control individuals. We found an increased number of Vdelta2+ cells in healthy contacts (PPD+ and lepromin+) and tuberculoid leprosy patients. The gammadelta T cells from lepromatous leprosy showed a decreased response to all antigens tested, but some of these patients exhibited a significant response to the 30-kD glycoprotein of Mycobacterium tuberculosis. Interestingly, the reactivity of gammadelta T cells against mycobacterial antigens was significantly increased by costimulatory signals generated through CD7, LFA-1, CD50 and CD69 in all groups. However, signalling through CD69 did not enhance the responsiveness of gammadelta lymphocytes from lepromatous patients. On the other hand, the in vitro blockade of IL-10 with a specific antibody enhanced the cell proliferation of gammadelta lymphocytes from lepromatous leprosy patients, whereas exogenous IL-10 had an opposite effect in most individuals studied. These results suggest the potential role of different cell membrane receptors in the regulation of gammadelta T cell proliferation induced by mycobacteria, as well as the possible involvement of IL-10 in this phenomenon.

Stimulation through CD50 preferentially induces apoptosis of TCR1+ human peripheral blood lymphocytes

Apoptosis has an important role in several key immunological phenomena such as regulation of the immune response, and deletion of auto-reactive cells. This phenomenon is induced following the interaction of several cell membrane receptors with their respective ligands or after cell activation. We have studied the possible effect of signaling through CD50/ICAM-3 and CD69/AIM on apoptosis of peripheral blood lymphocytes. Apoptosis was assessed by both flow cytometry analysis (content of cell DNA and binding to annexin V), and detection of DNA fragmentation by agarose gel electrophoresis. We found that a stimulatory anti-CD50 mAb was able to induce a small but significant degree of apoptosis in resting peripheral blood mononuclear cells from most donors; this effect was dose-dependent and was evident as early as at 12 h, with a maximal induction at 48 h. Studies with T and non-T cells showed that only the former cell population was sensitive to the induction of apoptosis through CD50. Further experiments revealed that the anti-ICAM-3 mAb preferentially induced apoptosis of TCR gamma delta-bearing cells. In addition, we found a significant increase in Cai2+ in PBMC stimulated with an anti-CD50 mAb, suggesting the involvement of this signaling pathway in the induction of apoptosis through this adhesion receptor. In contrast, under our experimental conditions, stimulation through CD69 did not have any effect on the induction of apoptosis on either cultured T lymphoblasts or PMA-stimulated PBMC. Our findings suggest that the interaction of CD50 with its natural ligand LFA-1 results in the induction of apoptosis in a significant fraction of resting PBMC. This phenomenon may be involved in immune regulation, lymphocyte turnover and peripheral deletion of auto-reactive cells.