Influência de polimorfismos em genes relacionados à inflamação na resposta à intervenção dietoterápica sem lactose em pacientes com síndrome metabólica

Abstract

Introduction: Metabolic Syndrome (MetS) is a set of alterations with a strong inflammatory basis. It has a complex aetiology, interacting with environmental and genetic factors. Among the environmental factors, diet is an important treatment option, with various types of diet, and the genotype of the individuals can influence the response. Polymorphisms in genes that regulate the production of inflammatory cytokines participate in this interaction. In this sense, the general objective of this thesis was to investigate whether polymorphisms in genes related to inflammation influence the response to lactose-free dietary intervention in patients with metabolic syndrome. Methods: Two studies were carried out. Article 1 is a scoping review protocol, which was conducted according to the method recommended by the Joanna Briggs Institute (JBI) and the checklist proposed by the Preferred Reporting Items for Systematic Reviews and Meta-Analyses Extension for Scoping Reviews (PRISMA-ScR). A preliminary search strategy was developed for PubMed and adapted for the other databases. Two independent reviewers will perform the screening and data extraction. Article 2 is a randomized clinical trial with adults and elderly people of both sexes, with MetS. Sociodemographic, anthropometric, clinical and nutritional data were collected and randomized into three groups, according to the type of diet: diet 1, lactose-free; diet 2, lactose-free and low-calorie; diet 3, low-calorie diet only. The participants underwent blood collection for biochemical tests and DNA extraction, as well as for analysis of polymorphisms: rs1800629 (TNF); rs1800896 (IL-10); rs1800795 (IL-6); and rs1143634 (IL 1β). After two months of following the diet, biochemical tests were repeated, and anthropometric data was collected. According to genotype, the chi-square or Fisher’s exact tests was used for categorical variables, Kruskal-Wallis for medians between groups, and Wilcoxon for differences in cofactors after the intervention. Data were analyzed using the R statistical program and the adequacy of the genotype frequencies of polymorphisms. Results: In article 1, a scoping protocol was presented according to the JBI method; in article 2, the study population consisted mostly of females (85%), black skin color (50%), with a mean age of 57.6 (±8.81) years. Regarding the lactose-free and low-calorie diet group, a statistically significant association was found between rs1800896 (IL-10 -1082 G/A) and waist circumference (p=0.01) and BMI (p=0.002); in the lactose-free diet group, rs1143634 (IL-1β +3954 C/T) with blood glucose (p=0.07) and triglycerides (p=0.050); and, in the low-calorie diet group, rs1800629 (TNF-308 G/A) with HOMA-IR (p=0.003). Conclusion: The scoping review protocol will allow the investigation of the hypocaloric diet and its effect on MetS. The data from article 2 demonstrated that the inflammatory genetic profile can influence the response to the lactose-free diet.