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Project
Association between intestinal parasites and inflammation and nutritional status in Mexican children
Intestinal parasitic infections and malnutrition, either presented as micronutrient deficiency, undernutrition, overweight or obesity are highly prevalent in children of low and middle income countries (1-3). Mexico has a combined prevalence of overweight and obesity in children of more than 30% (4), while micronutrient deficiencies such as iron (34-39%) zinc (19-24%) are also highly prevalent (5). In addition is estimated that at least half of the Mexican children are infected with at least one species of intestinal parasite. In some cases intestinal helminths and pathogenic protozoa cause abdominal pain, anorexia and compromise the intestinal epithelial cells (12). In contrast, non-pathogenic protozoa such as Entamoeba coli (E. coli) are asymptomatic, but may lead to malabsorption, changes in the gut microbiota and inflammation (13).
Parasitic infection and Inflammation
Intestinal helminths trigger innate immune response as well as Th2 systemic inflammation pathways leading to an increased production of Th2-type cytokines such as interleukin-4 and interleukin-10 (34). In addition experimental helminth infection is being tested as a new therapy against intestinal inflammatory diseases such as Crohn (35). In contrast, In-vitro and animal studies assessing non-intestinal protozoa such as Plasmodium spp and Leishmania major or pathogenic intestinal protozoa such as Entamoeba hystolitica shows that protective immunity against these protozoan parasites is usually triggered by Tumor Necrosis Factor alpha (TNF-α) promoting a Th1 systemic inflammatory response, involving effector cells such as granulocytes and lymphocytes and signaling molecules such as interleukin-6 and leptin (20, 36-38). However, to the best of our knowledge, epidemiological studies addressing the relationship of most intestinal protozoa parasites with local and systemic inflammation is lacking (36, 37). Here we are going to evaluate the association between helminth, and protozoa intestinal parasites with local (intestine) and systemic inflammation markers in school-aged children.
Intestinal parasitic infection and body composition
Recent studies have shown that specific viral and bacterial infections are associated with increased body fat or “obesity” (described as “infectobesity”) (12-15). However, studies on the association between parasite infections and body obesity scarce (16-18). Intestinal parasitic infections have been associated with micronutrient deficiencies and changes in gut microbiota and mucosa. Both micronutrient deficiencies and gut microbiota have been related to higher risk of obesity (19). In addition, helminths and protozoans may have a differential effect on leptin secretion (20), inflammation, food intake and nutrient absorption and metabolism (21). Intestinal parasites may as well have a long term effect on body composition. “Stress factors” such as infectious diseases and under-nutrition presented during a critical window of development such as childhood or puberty can lead to epigenetic modifications (24-26). These epigenetic alterations may be reflected as permanent programmed changes in metabolism and may lead to fat deposition over time (27, 28). For instance, undernutrition and infections in early childhood have been associated with higher odds of becoming overweight/obese (28, 29). Both, in a population of rural Mexico and in a representative sample of the whole Mexican population we assessed associations between endemic intestinal parasites and body composition
Intestinal parasites and micronutrients
Micronutrients are vitamins and minerals, which are essential to maintain the physiological functions and integrity of the organism. Micronutrient deficiencies can impair physical growth and may increases the risk and severity of diarrhea, pneumonia and other infections (30). An impaired micronutrient absorption has been associated with different intestinal parasites. Mainly related to weakened gastrointestinal function, damage to the gut mucosa and competition for available micronutrients with the parasites, or lower micronutrient and food intake due to symptoms such as abdominal pain and loss of appetite (22, 31-33). Most of the studies done in this field had been in helminth infections, however information concerning this associations with intestinal protozoa is lacking. For these reasons we are evaluating associations between endemic intestinal parasites in Mexico and micronutrient status. Given the high rates parasitic infection in Mexican children and the possible association with nutritional outcomes such as body fat, food intake, micronutrient status and inflammatory reactions it is important to study if these conditions are associated. We therefore, developed the following hypothesis and research questions.
Parasitic infection and Inflammation
Intestinal helminths trigger innate immune response as well as Th2 systemic inflammation pathways leading to an increased production of Th2-type cytokines such as interleukin-4 and interleukin-10 (34). In addition experimental helminth infection is being tested as a new therapy against intestinal inflammatory diseases such as Crohn (35). In contrast, In-vitro and animal studies assessing non-intestinal protozoa such as Plasmodium spp and Leishmania major or pathogenic intestinal protozoa such as Entamoeba hystolitica shows that protective immunity against these protozoan parasites is usually triggered by Tumor Necrosis Factor alpha (TNF-α) promoting a Th1 systemic inflammatory response, involving effector cells such as granulocytes and lymphocytes and signaling molecules such as interleukin-6 and leptin (20, 36-38). However, to the best of our knowledge, epidemiological studies addressing the relationship of most intestinal protozoa parasites with local and systemic inflammation is lacking (36, 37). Here we are going to evaluate the association between helminth, and protozoa intestinal parasites with local (intestine) and systemic inflammation markers in school-aged children.
Intestinal parasitic infection and body composition
Recent studies have shown that specific viral and bacterial infections are associated with increased body fat or “obesity” (described as “infectobesity”) (12-15). However, studies on the association between parasite infections and body obesity scarce (16-18). Intestinal parasitic infections have been associated with micronutrient deficiencies and changes in gut microbiota and mucosa. Both micronutrient deficiencies and gut microbiota have been related to higher risk of obesity (19). In addition, helminths and protozoans may have a differential effect on leptin secretion (20), inflammation, food intake and nutrient absorption and metabolism (21). Intestinal parasites may as well have a long term effect on body composition. “Stress factors” such as infectious diseases and under-nutrition presented during a critical window of development such as childhood or puberty can lead to epigenetic modifications (24-26). These epigenetic alterations may be reflected as permanent programmed changes in metabolism and may lead to fat deposition over time (27, 28). For instance, undernutrition and infections in early childhood have been associated with higher odds of becoming overweight/obese (28, 29). Both, in a population of rural Mexico and in a representative sample of the whole Mexican population we assessed associations between endemic intestinal parasites and body composition
Intestinal parasites and micronutrients
Micronutrients are vitamins and minerals, which are essential to maintain the physiological functions and integrity of the organism. Micronutrient deficiencies can impair physical growth and may increases the risk and severity of diarrhea, pneumonia and other infections (30). An impaired micronutrient absorption has been associated with different intestinal parasites. Mainly related to weakened gastrointestinal function, damage to the gut mucosa and competition for available micronutrients with the parasites, or lower micronutrient and food intake due to symptoms such as abdominal pain and loss of appetite (22, 31-33). Most of the studies done in this field had been in helminth infections, however information concerning this associations with intestinal protozoa is lacking. For these reasons we are evaluating associations between endemic intestinal parasites in Mexico and micronutrient status. Given the high rates parasitic infection in Mexican children and the possible association with nutritional outcomes such as body fat, food intake, micronutrient status and inflammatory reactions it is important to study if these conditions are associated. We therefore, developed the following hypothesis and research questions.
Datum:12 jan 2017 → 5 apr 2018
Trefwoorden:B780-tropische-geneeskunde