Adenilda Cristina Honorio-França

Oxidative and Nitrosative Stress on Phagocytes’ Function: from Effective Defense to Immunity Evasion Mechanisms

Although oxygen, nitrogen, and chlorine reactive species have been associated with disease pathogenesis, their partial absence is very harmful to the body’s innate immune defense. Lacking of adequate release of free radicals from activated phagocytes is related to impaired ability on fungi, bacteria, and protozoa killing. We constructed an updated conceptual landmark regarding the paramount role of free radicals in phagocyte defense systems (phagocyte oxidase, myeloperoxidase, and nitric oxide/peroxynitrite system) on natural immunity. Diverse fungal, bacterial and protozoal pathogens evade the phagocytes’ oxidative/nitrosative burst though antioxidant genes, enzymes and proteins. The most important evasion mechanisms were also described and discussed. These interconnected systems were reviewed and discussed on the basis of knowledge from relevant research groups around the globe. Phagocyte-derived free radicals are essential to destroy important human pathogens during the course of innate immunity.

Diabetes induced immunological and biochemical changes in human colostrum

Aim:  This article describes the changes and relationships between biochemical and immunological parameters in the colostrum and serum of diabetic women.

Phagocytosis of Giardia lamblia trophozoites by human colostral leukocytes.

Aim: To determine the phagocytic activity of the polymorphonuclear and mononuclear cells present in human colostrum, and to verify the influence of opsonins in the adherence, ingestion and killing of Giardia lamblia trophozoites. Methods: Polymorphonuclear and mononuclear phagocytes were incubated with G. lamblia trophozoites, in the presence as well as the absence of supernatant of human colostrum (the source of opsonins) for 30, 60 and 120 min. The trophozoites/phagocytes ratio was 1:1, and the percentage of phagocytosed trophozoites was determined by microscopic examination of acridine orange‐stained cells. Results: The mononuclear phagocytes presented more functional activity than the polymorphonuclear. The highest indexes of adherence (77.6±5.1), ingestion (68.9±5.5) and killing (48.5±4.9) were obtained through the incubation of mononuclear cells in the presence of colostrum supernatant for 120 min.

Transfer of Maternal Immunity to Newborns of Diabetic Mothers

This study was carried out with hyperglycemic pregnant women to investigate the transfer of antibody classes to newborns across the placenta or by colostrum and the functional activity of phagocytes in maternal blood, cord blood, and colostrum from diabetes mothers. Samples from maternal blood, cord blood, and colostrum were collected from 20 normoglycemic and 20 hyperglycemic pregnant women. We determined antibodies levels, superoxide release, phagocytosis and bactericidal activity of phagocytes. We demonstrated that IgG levels in cord blood were higher in the hyperglycemic group. IgA and IgM levels were higher in maternal than in cord blood samples. Plasma antibody levels were lower in hyper- than in normoglycemic women. The colostrum of diabetic mothers had lower IgA and IgG levels. Colostrum and maternal blood phagocytes when exposed to EPEC increased the superoxide release. Cord blood phagocytes of hyperglycemic group, independently of bacteria, had higher superoxide release. Colostrum and blood phagocytes from diabetic group exhibited some phagocytic and microbicidal activity in response to EPEC. Mononuclear phagocytes from cord blood had the lowest phagocytosis, and bactericidal activity for EPEC, regardless of glycemic status. These data showed that hyperglycemia altered IgG transfer across the placenta and decreases immunoglobulin levels in maternal blood and colostrum.

Antioxidant Effect of Melatonin on the Functional Activity of Colostral Phagocytes in Diabetic Women

Melatonin is involved in a number of physiological and oxidative processes, including functional regulation in human milk. The present study investigated the mechanisms of action of melatonin and its effects on the functional activity of colostral phagocytes in diabetic women. Colostrum samples were collected from normoglycemic (N = 38) and diabetic (N = 38) women. We determined melatonin concentration, superoxide release, bactericidal activity and intracellular Ca2+ release by colostral phagocytes treated or not with 8-(Diethylamino) octyl-3,4,5-trimethoxybenzoate hydrochloride (TMB-8) and incubated with melatonin and its precursor (N-acetyl-serotonin-NAS), antagonist (luzindole) and agonist (chloromelatonin-CMLT). Melatonin concentration was higher in colostrum samples from hyperglycemic than normoglycemic mothers. Melatonin stimulated superoxide release by colostral phagocytes from normoglycemic but not hyperglycemic women. NAS increased superoxide, irrespective of glycemic status, whereas CMTL increased superoxide only in cells from the normoglycemic group. Phagocytic activity in colostrum increased significantly in the presence of melatonin, NAS and CMLT, irrespective of glycemic status. The bactericidal activity of colostral phagocytes against enterophatogenic Escherichia coli (EPEC) increased in the presence of melatonin or NAS in the normoglycemic group, but not in the hyperglycemic group. Luzindole blocked melatonin action on colostrum phagocytes. Phagocytes from the normoglycemic group treated with melatonin exhibited an increase in intracellular Ca2+ release. Phagocytes treated with TMB-8 (intracellular Ca2+ inhibitor) decreased superoxide, bactericidal activity and intracellular Ca2+ release in both groups. The results obtained suggest an interactive effect of glucose metabolism and melatonin on colostral phagocytes. In colostral phagocytes from normoglycemic mothers, melatonin likely increases the ability of colostrum to protect against EPEC and other infections. In diabetic mothers, because maternal hyperglycemia modifies the functional activity of colostrum phagocytes, melatonin effects are likely limited to anti-inflammatory processes, with low superoxide release and bactericidal activity.

Secretory IgA-Fc alpha receptor interaction modulating phagocytosis and microbicidal activity by phagocytes in human colostrum of diabetics

França EL, Morceli G, Fagundes DLG, Rudge MVC, Calderon I de MP, Honorio‐França AC. Secretory IgA–Fcα receptor interaction modulating phagocytosis and microbicidal activity by phagocytes in human colostrum of diabetics. APMIS 2011; 119: 710–19.

Breastfeeding and its Relationship with Reduction of Breast Cancer: A Review

In this review, we describe the patterns of known immunological components in breast milk and examine the relationship between breastfeeding and reduced risk of breast cancer. The top risk factors for breast cancer are a womans age and family history, specifically having a first-degree relative with breast cancer. Women that have a history of breastfeeding have been shown to have reduced rates of breast cancer. Although the specific cause has not been elucidated, previous studies have suggested that breastfeeding reduces the risk of breast cancer primarily through two mechanisms: the differentiation of breast tissue and reduction in the lifetime number of ovulatory cycles. In this context, one of the primary components of human milk that is postulated to affect cancer risk is alpha-lactalbumin. Tumour cell death can be induced by HAMLET (a human milk complex of alpha-lactalbumin and oleic acid). HAMLET induces apoptosis only in tumour cells, while normal differentiated cells are resistant to its effects. Therefore, HAMLET may provide safe and effective protection against the development of breast cancer. Mothers should be encouraged to breastfeed their babies because the complex components of human milk secretion make it an ideal food source for babies and clinical evidence has shown that there is a lower risk of breast cancer in women who breastfed their babies.

Melatonin reduces the severity of experimental amoebiasis

BackgroundMelatonin has immunomodulatory effects but very little is known about its influence in protozoan infections, such as Entamoeba histolytica, which causes amoebiasis, a disease with significant morbidity and mortality. In this study, we evaluated the effects of exogenous melatonin interference in experimental amoebiasis and on interactions between human blood cells and E. histolytica trophozoites.MethodsThe effect of melatonin was investigated in models of experimental amoebiasis in hamsters and rats by evaluating the area of necrosis induced by E. histolytica. The activity of melatonin on the interactions between leukocytes and amoebae was determined by examining leukophagocytosis. For in vitro tests, polymorphonuclear and mononuclear human blood leucocytes were incubated with E. histolytica trophozoites.ResultsThe areas of amoebic necrosis were significantly reduced in animals treated with melatonin. Melatonin treatment increased leukophagocytosis but was associated with a greater number of dead amoebae.ConclusionsThese results suggest that melatonin may play a beneficial role in the control of amoebic lesions, raising the possibility that this drug may be used as an adjuvant in anti-amoebic therapy.

Evaluation of hypoglicemic activity and healing of extract from amongst bark of "Quina do Cerrado" (Strychnos pseudoquina ST. HILL)

PURPOSE Evaluation the hypoglycemic and healing effects of the Strychnos pseudoquina. METHODS 33 Wistar rats were divided in the following groups, group 1 not sensitized with alloxan and untreated by aqueous extracts; group 2 sensitized with aloxana and untreated by aqueous extracts of Quina; group 3 sensitized by aloxana ad treated with the aqueous extract of quina. Diabetes was induced by alloxan diabetogenic drugs at a dose of 42 mg/kg of weight. The glycemias was evaluated by glycemic measuring Accu-check. To verify the healing, was made a longitudinal cut of 1 cm in the back of the mouse. The group 3 was treated with a microemulsion containing Strychnos pseudoquina. Wounds were macroscopically evaluated during pre-determined days after the cut (1st, 3rd, 7th, 9th, 14th). RESULTS The glycemia levels in the group treated with Strychnos pseudoquina were lower than the group sensitized by alloxan and not treated with Strychnos pseudoquina. There was no difference between the healing of the wounds treated with quina and another groups. CONCLUSIONS Strychnos pseudoquina presents hypoglycemic effect. Meanwhile the topical use of the microemulsion of Strychnos pseudoquina presents no macroscopically significant effect on the healing of wounds in diabetic rats.

Percepção de estudantes do ensino fundamental quanto ao aleitamento materno e a influência da realização de palestras de educação em saúde

OBJECTIVE: To assess attitudes to breastfeeding among children in primary education and to evaluate the influence of educational lectures on their knowledge. METHODS: This was a cross-sectional study of 503 students of both sexes from the fourth to the eighth grades of five different schools. The children were divided into two groups: control (n = 215) and intervention (n = 288) in order to evaluate the influence of educational lectures. A questionnaire containing 30 questions about different features of breastfeeding was used for data collection. The intervention took the form of a 30-minute lecture, given at the schools. RESULTS: The lecture increased the number of schoolchildren who answered that breastmilk is most beneficial for infants (p < 0.05) and that breastfeeding is the most practical way of feeding babies (p < 0.05). There was a reduction in the number who would give supplementary feeding during the first month of life (p < 0.05) and also in how many would give a baby a pacifier (p < 0.05). After the intervention less than half of the girls would chose to breastfeed for 1 year or more (39.1% in the control group vs. 43.2% in the intervention group); while the opposite was true of the males (54.7% in the control group vs. 51.7% in the intervention group). More of the boys (37.1%) were able to cite specific advantages for mothers from breastfeeding when compared to the females (19.9%). CONCLUSION: The results indicate that lectures on health education, presented at schools, have a beneficial effect on breastfeeding knowledge, awareness and attitudes.