Parasiticidal effect of synthetic bovine lactoferrin peptides on the enteric parasite Giardia intestinalis.

Giardia intestinalis is the most common infectious protozoan parasite in children. Despite the effectiveness of some drugs, the disease remains a major worldwide problem. Consequently, the search for new treatments is important for disease eradication. Biological molecules with antimicrobial properties represent a promising alternative to combat pathogens. Bovine lactoferrin (bLF) is a key component of the innate host defense system, and its peptides have exhibited strong antimicrobial activity. Based on these properties, we evaluated the parasiticidal activity of these peptides on G. intestinalis. Trophozoites were incubated with different peptide concentrations for different periods of time, and the growth or viability was determined by carboxyfluorescein-succinimidyl-diacetate-ester (CFDA) and propidium iodide (PI) staining. Endocytosis of peptides was investigated by confocal microscopy, damage was analyzed by transmission and scanning electron microscopy, and the type of programmed cell death was analyzed by flow cytometry. Our results showed that the LF peptides had giardicidal activity. The LF peptides interacted with G. intestinalis and exposure to LF peptides correlated with an increase in the granularity and vacuolization of the cytoplasm. Additionally, the formation of pores, extensive membrane disruption, and programmed cell death was observed in trophozoites treated with LF peptides. Our results demonstrate that LF peptides exhibit potent in vitro antigiardial activity.

[Three-dimensional analysis of human chorioamniotic membranes structure in term pregnancy]. / Análisis tridimensional de la estructura de las membranas corioamnióticas humanas al término de la gestación.

BACKGROUND: Physical and structural chorioamniotic membranes integrity is due to a precise process of synthesis and degradation of collagen; surrounding collagenolitic activity raises during labor, what leads to a structural loss and mechanical resistance weakening, the main cause of its rupture under physiological and pathological conditions. Understanding of its three-dimensional structure is essential to characterize normal and pathological labor. OBJECTIVE: To analyze three-dimensional structure of human chorioamniotic membranes at gestational term. MATERIAL AND METHODS: Descriptive study to analyze the distribution of collagens type I, II and IV in human chorioamniotic membranes at term (37 to 40 gestational weeks) without labor by means of confocal and electronic scan microscopy. RESULTS: Cells' amnios shapes a homogeneous epithelium without a close intercellular contact (classic epithelium) what may contribute to transmembranal diffusion molecules' transport. Amnios connective tissue is too a complex fibrilar net of type I collagen, structurally supported by type IV collagen. On the contrary, corion has a great amount of cells in close contact, with a few fibers of type I and II collagen, and almost none of type IV collagen cells. CONCLUSION: Three-dimensional analysis of chorioamniotic membranes connective tissue, particularly amnios, allows to understand the main role of type IV collagen on supporting its structure, as well as collagenolitic enzymes in its degradation and rupture under normal and pathological conditions.