Biochemical and histological changes in liver ofNectomys squamipes naturally infected bySchistosoma mansoni

Abstract

The South American water rat Nectomys squamipes is a wild mammal reservoir of Schistosoma mansoni in Brazil. In the present study, wild rodents were collected in the field and categorized into two groups: infected and uninfected by S. mansoni. Blood was collected to analyze changes in the serum glucose level (mg/dL) and liver fragments were used to determine the hepatic glycogen content (mg of glucose/g tissue). The histological examination showed inflammatory granulomatous lesions in different phases of development in the liver of rodents naturally infected with S. mansoni, in some cases with total or partial occlusion of the vascular lumen. Early lesions were characterized by the presence of inflammatory infiltrate around morphologically intact recently deposited eggs. Despite the significance of these histological lesions, the biochemical changes differed in extent. N. squamipes naturally infected by S. mansoni showed no variation in hepatic glycogen reserves. These findings were accompanied by a significant increase in plasma glucose contents, probably as a consequence of amino acids deamination, which are degraded, resulting in the formation of intermediates used as precursors for the glucose formation, without compromising the reserves of liver glycogen. In the wild, naturally infected N. squamipes can maintain S. mansoni infections without undergoing alterations in its carbohydrate metabolism, which minimizes the deleterious effects of S. mansoni.Keywords: Biochemical alterations, rodents, wild reservoirs, alternative model. ResumoNectomys squamipes é um mamífero silvestre reservatório de Schistosoma mansoni no Brasil. No presente estudo, os roedores silvestres, colhidos no campo, foram classificados em dois grupos: infectado e não infectado por S. mansoni. O sangue foi colhido para análise da alteração no nível de glicose sérico (mg/dL) e fragmentos de fígado foram usados para determinar o conteúdo de glicogênio hepático (mg de glicose/g tecido). A análise histológica demonstrou lesões granulomatosas em diferentes fases de desenvolvimento no tecido hepático dos roedores naturalmente infectados com S. mansoni, localizados principalmente na região periportal, com total ou parcial oclusão do lúmen vascular. As lesões foram caracterizadas por presença de infiltrado inflamatório ao redor de ovos morfologicamente intactos recentemente depositados. Apesar da grande significância das lesões histológicas, as alterações bioquímicas não diferiram no mesmo

Natural Schistosoma mansoni Infection in the Wild Reservoir Nectomys squamipes Leads to Excessive Lipid Droplet Accumulation in Hepatocytes in the Absence of Liver Functional Impairment

“…mansoni -infected N . squamipes is a well-characterized lesion as previously documented for this rodent [21, 22]. Granulomas in different developmental phases including involutional types were clearly observed in the liver and inflammatory cells composed of eosinophils and mononuclear cells were seen around deposited eggs (Fig 1).…”

“…squamipes is highly susceptible to the experimental S . mansoni infection [11, 43–45] and that both experimental and natural infection of this wild reservoir reproduce the granulomatous reaction observed in experimental infections in other models, such as mice [21, 22]. Moreover, S .…”

Histological assessment of granulomas in natural and experimental Schistosoma mansoni infections using whole slide imaging

“…mansoni -infected N . squamipes is a well-characterized lesion as previously documented for this rodent [ 23 , 24 ]. The liver of the S .…”

“…One intriguing aspect of this helminthiasis in N . squamipes is that this wild reservoir is highly susceptible to this infection, but presents a notable physiological adaptation to the parasite [ 19 , 24 ].…”

Perfil Glicêmico De Biomphalaria Glabrata (Gastropoda: Planorbidae) Expostas a Heterorhabditis Bacteriophora (Rhabditida: Heterorhaditidae): Potencial Controle Da Esquistossomose / Glycemic Profile of Biomphalaria Glabrata (Gastropoda: Planorbidae) Exposed to Heterorhabditis Bacteriophora (Rhabditida: Heterorhabditidae): Potential Control of Schistosomiasis

“…O caráter endêmico da esquistossomose no Brasil prevalece devido à vários fatores, incluindo: clima tropical, presença de hospedeiros intermediários do parasito, além da ausência de políticas públicas relacionadas ao saneamento básico. De acordo com Costa-Neto et al (2013), a existência de reservatórios silvestres como Nectomys squamipes, roedores de comportamento semi-aquático, também aumentam a dispersão de ovos em coleções hídricas, contribuindo para o cenário atual da doença no Brasil. Como alternativa na erradicação da doença, a Organização Mundial da Saúde preconiza o desenvolvimento de metodologias pautadas no controle da população de moluscos hospedeiros intermediários (WHO, 1983).…”