A High-Fat Diet Exacerbates the Course of Experimental Trypanosoma cruzi Infection That Can Be Mitigated by Treatment with Simvastatin.

The protozoan Trypanosoma cruzi is responsible for triggering a damage immune response in the host cardiovascular system. This parasite has a high affinity for host lipoproteins and uses the low-density lipoprotein (LDL) receptor for its invasion. Assuming that the presence of LDL cholesterol in tissues could facilitate T. cruzi proliferation, dietary composition may affect the parasite-host relationship. Therefore, the aim of this study was to evaluate myocarditis in T. cruzi-infected C57BL/6 mice-acute phase-fed a high-fat diet and treated with simvastatin, a lipid-lowering medication. Animals (n = 10) were infected with 5 × 103 cells of the VL-10 strain of T. cruzi and treated or untreated daily with 20 mg/kg simvastatin, starting 24 h after infection and fed with a normolipidic or high-fat diet. Also, uninfected mice, treated or not with simvastatin and fed with normolipidic or high-fat diet, were evaluated as control groups. Analyses to measure the production of chemokine (C-C motif) ligand 2 (CCL2), interferon- (IFN-) γ, interleukin- (IL-) 10, and tumor necrosis factor (TNF); total hepatic lipid dosage; cholesterol; and fractions, as well as histopathological analysis, were performed on day 30 using cardiac and fat tissues. Our results showed that the high-fat diet increased (i) parasite replication, (ii) fat accumulation in the liver, (iii) total cholesterol and LDL levels, and (iv) the host inflammatory state through the production of the cytokine TNF. However, simvastatin only reduced the production of CCL2 but not that of other inflammatory mediators or biochemical parameters. Together, our data suggest that the high-fat diet may have worsened the biochemical parameters of the uninfected and T. cruzi-infected animals, as well as favored the survival of circulating parasites.

Deficiency of CD73 activity promotes protective cardiac immunity against Trypanosoma cruzi infection but permissive environment in visceral adipose tissue.

Damaged cells release the pro-inflammatory signal ATP, which is degraded by the ectonucleotidases CD39 and CD73 to the anti-inflammatory mediator adenosine (ADO). The balance between ATP/ADO is known to determine the outcome of inflammation/infection. However, modulation of the local immune response in different tissues due to changes in the balance of purinergic metabolites has yet to be investigated. Here, we explored the contribution of CD73-derived ADO on the acute immune response against Trypanosoma cruzi parasite, which invades and proliferates within different target tissues. Deficiency of CD73 activity led to an enhanced cardiac microbicidal immune response with an augmented frequency of macrophages with inflammatory phenotype and increased CD8+ T cell effector functions. The increment of local inducible nitric oxide (NO) synthase (iNOS)+ macrophages and the consequent rise of myocardial NO production in association with reduced ADO levels induced protection against T. cruzi infection as observed by the diminished cardiac parasite burden compared to their wild-type (WT) counterpart. Unexpectedly, parasitemia was substantially raised in CD73KO mice in comparison with WT mice, suggesting the existence of tissue reservoir/s outside myocardium. Indeed, CD73KO liver and visceral adipose tissue (VAT) showed increased parasite burden associated with a reduced ATP/ADO ratio and the lack of substantial microbicidal immune response. These data reveal that the purinergic system has a tissue-dependent impact on the host immune response against T. cruzi infection.

Equine Mesenchymal Stromal Cells Retain a Pericyte-Like Phenotype.

Mesenchymal stem/stromal cells (MSCs) have been used in human and equine regenerative medicine, and interest in exploiting their potential has increased dramatically over the years. Despite significant effort to characterize equine MSCs, the actual origin of these cells and how much of their native phenotype is maintained in culture have not been determined. In this study, we investigated the relationship between MSCs, derived from adipose tissue (AT) and bone marrow (BM), and pericytes in the horse. Both pericyte (CD146, NG2, and αSMA) and MSC (CD29, CD90, and CD73) markers were detected in equine AT and colocalized around blood vessels. Importantly, as assessed by flow cytometry, both pericyte (CD146, NG2, and αSMA) and MSC (CD29, CD44, CD90, and CD105) markers were present in a majority (≥90%) of cells in cultures of AT-MSCs and BM-MSCs; however, levels of pericyte markers were variable within each of those populations. Moreover, the expression of pericyte markers was maintained for at least eight passages in both AT-MSCs and BM-MSCs. Hematopoietic (CD45) and endothelial (CD144) markers were also detected at low levels in MSCs by quantitative polymerase chain reaction (qPCR). Finally, in coculture experiments, AT-MSCs closely associated with networks produced by endothelial cells, resembling the natural perivascular location of pericytes in vivo. Our results indicate that equine MSCs originate from perivascular cells and moreover maintain a pericyte-like phenotype in culture. Therefore, we suggest that, in addition to classical MSC markers, pericyte markers such as CD146 could be used when assessing and characterizing equine MSCs.

Trypanosoma cruzi -infected Triatoma gerstaeckeri (Hemiptera: Reduviidae) from Nuevo León, México, and pathogenicity of the regional strain / Triatoma gerstaeckeri (Hemiptera: Reduviidae) infectada con Trypanosoma cruzi en Nuevo León, México, y capacidad patógena de la cepa regional

Introduction: Four species of triatomines have been reported in Nuevo León, northeast (NE) México, but Triatoma gerstaeckeri has only been recorded from a peridomestic dwelling. Objectives: To assess the natural infection index (NII) of Trypanosoma cruzi in triatomines and the infestation index (II) of T. gerstaeckeri collected in a suburban locality, and to collect histopathological data to understand tissue tropism of the regional T. cruzi strain (strain NE) obtained from the vectors collected after an experimental inoculation in Mus musculus . Materials and methods: Triatomines were collected from 85 houses and peridomiciles in Allende, Nuevo León. Stool samples were obtained to determine the T. cruzi NII and were used in an experimental mice infection. Results: A total of 118 T . gerstaeckeri were captured, and 46 (adults and nymphs) were collected inside the same house (II=1.17%). Thirty-seven reduvids were infected with T. cruzi (NII=31.3%). Tissue tropism of the T. cruzi NE strain was progressive in skeletal muscle, myocardial, and adipose tissues and was characterized by the presence of intracellular amastigotes and destruction of cardiac myocells. Conclusions: The presence of naturally infected domiciliary vectors is an important risk factor for public health in the region considering that these vectors are the principal transmission mechanism of the parasite. The T. cruzi NE strain has similar virulence to that of other Mexican and Texan strains and caused chagasic infections in 11 of 12 mice.

Introducción. En Nuevo León, localizado en el noreste de México, existen cuatro especies de triatominos, de las cuales Triatoma gerstaeckeri ha sido la única reportada en peridomicilios. Objetivos. Evaluar el índice de infección natural de Trypanosoma cruzi en los triatominos y el índice de infestación de T. gerstaeckeri en una localidad suburbana, y obtener datos histopatológicos para comprender el tropismo tisular de la cepa regional (cepa NE) de T. cruzi obtenida de los vectores recolectados después de la infección experimental en Mus musculus. Materiales y métodos. La recolección de triatominos se llevó a cabo en 85 casas y peridomicilios de Allende, Nuevo León, México. Se obtuvieron muestras de las deyecciones para conocer el índice de infección natural por T. cruzi y, con estas, se hicieron inoculaciones experimentales en ratones. Resultados. Se capturaron 118 especímenes de T. gerstaeckeri , 46 (adultos y ninfas) en el mismo domicilio (índice de infestación=1,17 %). Treinta y siete redúvidos estaban infectados con T. cruzi (índice de infección natural, 31,3). El tropismo tisular de la cepa NE de T. cruzi fue progresivo en músculo esquelético, miocardio y tejido adiposo, y se caracterizó por la presencia de amastigotes intracelulares con destrucción de células cardiacas. Conclusiones. La presencia de vectores domiciliarios naturalmente infectados con T. cruzi , es un factor de riesgo importante para la salud pública de la región, considerando que este es el principal mecanismo de la transmisión del parásito y que la cepa NE de T. cruzi tiene una virulencia similar a la de otras cepas mexicanas y texanas, y causó infección chagásica en 11 de los 12 ratones inoculados.

Immune response in the adipose tissue of lean mice infected with the protozoan parasite Neospora caninum.

The adipose tissue can make important contributions to immune function. Nevertheless, only a limited number of reports have investigated in lean hosts the immune response elicited in this tissue upon infection. Previous studies suggested that the intracellular protozoan Neospora caninum might affect adipose tissue physiology. Therefore, we investigated in mice challenged with this protozoan if immune cell populations within adipose tissue of different anatomical locations could be differently affected. Early in infection, parasites were detected in the adipose tissue and by 7 days of infection increased numbers of macrophages, regulatory T (Treg) cells and T-bet(+) cells were observed in gonadal, mesenteric, omental and subcutaneous adipose tissue. Increased expression of interferon-γ was also detected in gonadal adipose tissue of infected mice. Two months after infection, parasite DNA was no longer detected in these tissues, but T helper type 1 (Th1) cell numbers remained above control levels in the infected mice. Moreover, the Th1/Treg cell ratio was higher than that of controls in the mesenteric and subcutaneous adipose tissue. Interestingly, chronically infected mice presented a marked increase of serum leptin, a molecule that plays a role in energy balance regulation as well as in promoting Th1-type immune responses. Altogether, we show that an apicomplexa parasitic infection influences immune cellular composition of adipose tissue throughout the body as well as adipokine production, still noticed at a chronic phase of infection when parasites were already cleared from that particular tissue. This strengthens the emerging view that infections can have long-term consequences for the physiology of adipose tissue.

Chagas disease, adipose tissue and the metabolic syndrome

Trypanosoma cruzi infection of the adipose tissue of mice triggers the local expression of inflammatory mediators and a reduction in the expression of the adipokine adiponectin. T. cruzi can be detected in adipose tissue by PCR 300 days post-infection. Infection of cultured adipocytes results in increased expression of cytokines and chemokines and a reduction in the expression of adiponectin and the peroxisome proliferator-activated receptor ³, both of which are negative regulators of inflammation. Infection also results in the upregulation of cyclin D1, the Notch pathway, and extracellular signal-regulated kinase and a reduction in the expression of caveolin-1. Thus, T. cruzi infection of cultured adipocytes leads to an upregulation of the inflammatory process. Since adiponectin null mice have a cardiomyopathic phenotype, it is possible that the reduction in adiponectin contributes to the pathogenesis of chagasic cardiomyopathy. Adipose tissue may serve as a reservoir for T. cruzi from which parasites can become reactivated during periods of immunosuppression. T. cruzi infection of mice often results in hypoglycemia. In contrast, hyperglycemia as observed in diabetes results in increased parasitemia and mortality. Adipose tissue is an important target tissue of T. cruzi and the infection of this tissue is associated with a profound impact on systemic metabolism, increasing the risk of metabolic syndrome.

Trypanosoma cruzi infection of cultured adipocytes results in an inflammatory phenotype.

Infection with Trypanosoma cruzi, the etiologic agent of Chagas disease is accompanied by an intense inflammatory reaction. Our laboratory group has identified adipose tissue as one of the major sites of inflammation during disease progression. Because adipose tissue is composed of many cell types, we were interested in investigating whether the adipocyte per se was a source of inflammatory mediators in this infection. Cultured adipocytes were infected with the Tulahuen strain of T. cruzi for 48-96 h. Immunoblot and quantitative PCR (qPCR) analyses demonstrated an increase in the expression of proinflammatory cytokines and chemokines, including interleukin (IL)-1 beta, interferon-gamma, tumor necrosis factor-alpha, CCL2, CCL5, and CXCL10 as well as an increase in the expression of Toll-like receptors-2 and 9 and activation of the notch pathway. Interestingly, caveolin-1 expression was reduced while cyclin D1 and extracellular signal-regulated kinase (ERK) expression was increased. The expression of PI3kinase and the activation of AKT (phosphorylated AKT) were increased suggesting that infection may induce components of the insulin/IGF-1 receptor cascade. There was an infection-associated decrease in adiponectin and peroxisome proliferator-activated receptor-gamma (PPAR-gamma). These data provide a mechanism for the increase in the inflammatory phenotype that occurs in T. cruzi-infected adipocytes. Overall, these data implicate the adipocyte as an important target of T. cruzi, and one which contributes significantly to the inflammatory response observed in Chagas disease.

Dirofilaria repens presenting as a premasseteric nodule.

Dirofilariasis is a rare zoonosis that is mainly seen with subcutaneous or pulmonary involvement. Natural hosts are dogs, cats, jackals, and raccoons; however, humans can rarely become an accidental host for the parasite. In the reported case, infection manifested as a subcutaneous nodule, representing a significant diagnostic challenge for both the surgeon and the pathologist. A case of a 62-year-old man with a premasseteric soft tissue mass caused by Dirofilaria repens is presented with histopathologic confirmation.

Musculoskeletal and adipose tissue hydatidosis based on the iatrogenic spreading of cystic fluid during surgery: report of a case.

Hydatidosis or echinococcosis is a parasitic disease caused by Echinococcus granulosus or E. multilocularis, which forms cysts in the liver and lung after penetrating the duodenal mucosa and entering the portal circulation. The liver and lung act as a filter but some embryos enter the general circulation and disseminate throughout the body. Musculoskeletal involvement is a rare manifestation of hydatidosis, which is usually reported to affect a single muscle. We report here a rare case of a 68-year-old man with widespread hydatidosis of the retroperitoneum and the subcutaneous adipose tissue, and with multiple muscle involvement in the absence of liver, lung, and spleen involvement. The patient underwent surgical excision of a subcutaneous hydatid cyst 7 years earlier. It is likely that the large dissemination of parasites resulted from accidental rupture of the primary focus during surgery with consequent release and spreading of scolices via lymphatics.

The fatty acids of each lipid fraction and their use in providing energy source of the plerocercoid of Spirometra erinacei.

The fatty acid concentration of each lipid fraction of plerocercoids of Spirometra erinacei and the host snake serum was investigated. The major fatty acids of phospholipid of the plerocercoids were C18:1, C18:0 and C16:0, and those of the host snake serum were C16:0, C18:1 and C18:0, in order of amount in both cases. The changes of the fatty acid composition of phospholipid of the plerocercoids when they were incubated in physiological saline at 18 degrees C and at 37 degrees C for 24 h were investigated in both cases. Polyunsaturated fatty acids increased at 18 degrees C, and saturated fatty acids increased at 37 degrees C. Michaelis constants (Km) of beta-hydroxyacyl-CoA dehydrogenase (HAD), NADH: ubiquinone oxidoreductase (complex I) (NADH: ferricyanide reaction) and complex I (NADH: ubiquinone reaction) for NADH were 20.6, 50 and 13.3 microM, respectively. The ATP production in mitochondria of the plerocercoids was accelerated by adding ADP and inhibited by adding such electron transport system inhibitors as rotenone, antimycin A and sodium cyanide. These results suggested that the fatty acids in the plerocercoids played an important role in regulating the fluidity of membrane by changing the composition in membrane lipid corresponding with the change of temperature circumstance. The NADH reduced by HAD might be accepted by the complex I in the electron transport system, and thus the parasites were capable of ATP production in a classical pathway of the oxidative phosphorylation system.

Pathology of subcutaneous sparganosis: report of two cases.

Two cases of subcutaneous sparganosis were discovered at the Taipei Institute of Pathology in early spring of 1992. They had been resected under the impression of lipomas of the chest and abdomen. Both lesions contained characteristic plerocercoid larva (sparganum) of Spirometra sp., presumably Spirometra mansoni. Characteristic tissue reactions included necrosis, granulomatous reaction, and lymphoplasma cell infiltrates with focal collections of eosinophils. Since the worm can be readily dislodged from the tissues, an accurate diagnosis may not be possible in every instance. Thus, the prevalence of the disease may have been underestimated. Consuming raw flesh of infected second intermediate hosts or paratenic hosts and drinking unboiled water contaminated by infected Cyclops seems to favor the endemic occurrence of the disease in Taiwan.

The recruitment of mast cells, exclusively of the mucosal phenotype, into granulomatous lesions caused by the pentastomid parasite Porocephalus crotali: recruitment is irrespective of site.

Adults of the porocephalid pentastomid Porocephalus crotali infect the lung of rattlesnake definitive hosts and larvae develop in rat intermediate hosts. In the latter, nymphs encyst within a variety of tissue sites (commonly abdominal fat bodies and lungs) and each becomes the focus of an eosinophilic granuloma. From an early stage in infections, granulomas become increasingly infiltrated by mast cells which, using conventional histology and paired immunofluorescence against mast cell proteases, appear to be exclusively of the mucosal phenotype. Mucosal mast cells are concentrated along the dorsal region of the parasite and in a plug of tissue containing degenerating cuticles within independent granulomas, which is located between its head and tail. ELISAs against the rat mast cell proteases I and II (RMCP I and II), extracted from abdominal fat, lung, spleen, liver and kidney granulomas at various intervals post-infection, reveal a substantially elevated concentration of RMCP II in all lesions. In fat, concentrations increase up to about 100 days post-infection, at which time moulting ceases and inflammatory responses subside. RMCP II was scarcely detectable in matched control tissues. Unlike infections with certain nematode parasites, where enteric mucosal mast cells secrete RMCP II systemically, concentrations of RMCP II in the serum of infected rats were significantly reduced when compared with age-matched uninfected controls. These results confirm that P. crotali can selectively recruit mucosal mast cells to a variety of tissue sites, most of which are non-mucosal. Possible mechanisms are discussed.

Light microscope observations of granulomatous reactions against developing Porocephalus crotali (Pentastomida: Porocephalida) in mouse and rat.

The development of granulomatous reactions against moulting nymphal pentastomids (Porocephalus crotali) in the tissues of rat and mouse intermediate hosts is described. Adipose tissue and lungs are favoured sites for encystment accounting for 70% of larvae. Six moults separate the primary larva from the final infective stage which first appears about 80 days post-infection (p.i.) and is fully infective by day 120. Larvae, and particularly their cast cuticles, are the foci of granulomatous reactions characterized by an intense eosinophilia. During ecdysis, large numbers of eosinophils permeate the entire lesion but, significantly, degranulation is limited to the underside of cast cuticles where the resultant debris is endocytosed by macrophage/epithelioid cells. A pronounced asymmetry in the granulomatous lesion, evident even in the earliest cysts, results from the accumulation of individual epithelioid granulomas associated with cuticle fragments close to the ventral side of the developing parasite; each is circumscribed by fibrosis. External to this region are extensive tracts of tissue composed of mature plasma cells. Particularly in rats, large numbers of partially degranulated mast cells (= globule leucocytes) also surround cuticle granulomas, and mast cell granules can accumulate within macrophages and fibroblasts. Inflammation slowly subsides once the infective stage is attained. This 1 cm-long larva resides in a thin, fibrotic, C-shaped cyst and can remain viable for years: uniquely this instar retains its last moulted cuticle as a protective sheath. Nymphal instars II-VI feed predominantly upon eosinophils but we do not yet know whether this requirement is obligate.

[Pathogenicity of hemosporidians (Sporozoa, Haemosporidia) of birds]. / K voprosu o patogennosti gemosporidii (Sporozoa, Haemosporidia) ptits.

Ultrastructure of the cyst's wall was studied in monocercus type larvae of 5 species of the family Dilepididae: Dichoanotaenia tundra, Particterotaenia porosa, Platyscolex ciliata, Sacciuterina stellifera and Trichocephaloides megalocephala. In all examined cysticercoids the cyst's wall is of identical structure. It differs from the cyst's wall of larvae of the family Hymenolepididae by the character of material filling tegument, by fibrous and muscular, elements forming independent layers, by the absence of myelin-like layer limiting the cyst cavity. In addition to cytons and myofibroblasts in the cyst parenchima there are secretory cells producing electronic dense granules similar to those produced by neurosecretory cells of tape forms of cestodes.