[Alterations in cholesterol, triglyceride and total phospholipid levels in plasma of Callithrix jacchus (sagüi) reinfected by Schistosoma mansoni]

Characterizing genetic variation on the Z chromosome in Schistosoma japonicum reveals host-parasite co-evolution

BACKGROUND

Schistosomiasis is a neglected tropical disease that afflicts millions of people worldwide; it is caused by Schistosoma, the only dioecious flukes with ZW systems. Schistosoma japonicum is endemic to Asia; the Z chromosome of S. japonicum comprises one-quarter of the entire genome. Detection of positive selection using resequencing data to understand adaptive evolution has been applied to a variety of pathogens, including S. japonicum. However, the contribution of the Z chromosome to evolution and adaptation is often neglected.

METHODS

We obtained 1,077,526 high-quality SNPs on the Z chromosome in 72 S. japonicum using re-sequencing data publicly. To examine the faster Z effect, we compared the sequence divergence of S. japonicum with two closely related species, Schistosoma haematobium and S. mansoni. Genetic diversity was compared between the Z chromosome and autosomes in S. japonicum by calculating the nucleotide diversity (π) and Dxy values. Population structure was also assessed based on PCA and structure analysis. Besides, we employed multiple methods including Tajima's D, FST, iHS, XP-EHH, and CMS to detect positive selection signals on the Z chromosome. Further RNAi knockdown experiments were performed to investigate the potential biological functions of the candidate genes.

RESULTS

Our study found that the Z chromosome of S. japonicum showed faster evolution and more pronounced genetic divergence than autosomes, although the effect may be smaller than the variation among genes. Compared with autosomes, the Z chromosome in S. japonicum had a more pronounced genetic divergence of sub-populations. Notably, we identified a set of candidate genes associated with host-parasite co-evolution. In particular, LCAT exhibited significant selection signals within the Taiwan population. Further RNA interference experiments suggested that LCAT is necessary for S. japonicum survival and propagation in the definitive host. In addition, we identified several genes related to the specificity of the intermediate host in the C-M population, including Rab6 and VCP, which are involved in adaptive immune evasion to the host.

CONCLUSIONS

Our study provides valuable insights into the adaptive evolution of the Z chromosome in S. japonicum and further advances our understanding of the co-evolution of this medically important parasite and its hosts.

Effects of helminths and anthelmintic treatment on cardiometabolic diseases and risk factors: A systematic review

BACKGROUND

Globally, helminth infections and cardiometabolic diseases often overlap in populations and individuals. Neither the causal relationship between helminth infections and cardiometabolic diseases nor the effect of helminth eradication on cardiometabolic risk have been reviewed systematically in a large number of human and animal studies.

METHODS

We conducted a systematic review assessing the reported effects of helminth infections and anthelmintic treatment on the development and/or severity of cardiometabolic diseases and risk factors. The search was limited to the most prevalent human helminths worldwide. This study followed PRISMA guidelines and was registered prospectively in PROSPERO (CRD42021228610). Searches were performed on December 10, 2020 and rerun on March 2, 2022 using Ovid MEDLINE ALL (1946 to March 2, 2022), Web of Science, Cochrane Library, Global Index Medicus, and Ovid Embase (1974 to March 2, 2022). Randomized clinical trials, cohort, cross-sectional, case-control, and animal studies were included. Two reviewers performed screening independently.

RESULTS

Eighty-four animal and human studies were included in the final analysis. Most studies reported on lipids (45), metabolic syndrome (38), and diabetes (30), with fewer on blood pressure (18), atherosclerotic cardiovascular disease (11), high-sensitivity C-reactive protein (hsCRP, 5), and non-atherosclerotic cardiovascular disease (4). Fifteen different helminth infections were represented. On average, helminth-infected participants had less dyslipidemia, metabolic syndrome, diabetes, and atherosclerotic cardiovascular disease. Eleven studies examined anthelmintic treatment, of which 9 (82%) reported post-treatment increases in dyslipidemia, metabolic syndrome, and diabetes or glucose levels. Results from animal and human studies were generally consistent. No consistent effects of helminth infections on blood pressure, hsCRP, or cardiac function were reported except some trends towards association of schistosome infection with lower blood pressure. The vast majority of evidence linking helminth infections to lower cardiometabolic diseases was reported in those with schistosome infections.

CONCLUSIONS

Helminth infections may offer protection against dyslipidemia, metabolic syndrome, diabetes, and atherosclerotic cardiovascular disease. This protection may lessen after anthelmintic treatment. Our findings highlight the need for mechanistic trials to determine the pathways linking helminth infections with cardiometabolic diseases. Such studies could have implications for helminth eradication campaigns and could generate new strategies to address the global challenge of cardiometabolic diseases.

Alterations in serum paraoxonase-1 activity and lipid profile in chronic alcoholic patients infected with Strongyloides stercoralis

The objective of this study was to investigate paraoxonase-1 (PON1) activity, cortisol levels, and the lipid profile in the sera of alcoholic and non-alcoholic Strongyloides stercoralis-infected and uninfected individuals in a sample of 276 individuals attended at the National Health System in Salvador, Bahia, Brazil. The activity of PON1 was measured by the Beltowski method, serum lipids, and cortisol levels using commercial kits. PON1 activity was low in both alcoholic and non-alcoholic individuals infected with S. stercoralis. A positive correlation was observed between PON1 activity and cortisol concentration in alcoholic individuals who were not infected with S. stercoralis; whereas a negative correlation occurred in S. stercoralis-infected nonalcoholic individuals. The levels of triglycerides, LDL-C, and VLDL-C in S. stercoralis-infected alcoholic individuals were significantly lower than in uninfected alcoholic individuals. The high level of HDL-C and the low level of LDL-C, VLDL, triglycerides and PON1 activity in alcoholic patients infected with S. stercoralis evidenced an anti-atherogenic pattern.

Isoforms of Hsp70-binding human LDL in adult Schistosoma mansoni worms

Schistosoma mansoni is one of the most common parasites infecting humans. They are well adapted to the host, and this parasite's longevity is a consequence of effective escape from the host immune system. In the blood circulation, lipoproteins not only help to conceal the worm from attack by host antibodies but also act as a source of lipids for S. mansoni. Previous SEM studies showed that the low-density lipoprotein (LDL) particles present on the surface of adult S. mansoni worms decreased in size when the incubation time increased. In this study, immunocytochemical and proteomic analyses were used to locate and identify S. mansoni binding proteins to human plasma LDL. Ultrathin sections of adult worms were cut transversely from the anterior, medial and posterior regions of the parasite. Immunocytochemical experiments revealed particles of gold in the tegument, muscle region and spine in male worms and around vitelline cells in females. Immunoblotting and 2D-electrophoresis using incubations with human serum, anti-LDL antibodies and anti-chicken IgG peroxidase conjugate were performed to identify LDL-binding proteins in S. mansoni. Analysis of the binding proteins using LC-MS identified two isoforms of the Hsp70 chaperone in S. mansoni. Hsp70 is involved in the interaction with apoB in the cytoplasm and its transport to the endoplasmic reticulum. However, further studies are needed to clarify the functional role of Hsp70 in S. mansoni, mainly related to the interaction with human LDL.

Human plasma lipid modulation in schistosomiasis mansoni depends on apolipoprotein E polymorphism

Background

Schistosomiasis mansoni is a parasitic liver disease, which causes several metabolic disturbances. Here, we evaluate the influence of Apolipoprotein E (APOE) gene polymorphism, a known modulator of lipid metabolism, on plasma lipid levels in patients with hepatosplenic schistosomiasis.

Methodology/Principal Findings

Blood samples were used for APOE genotyping and to measure total cholesterol (TC), LDL-C, HDL-C and triglycerides. Schistosomiasis patients had reduced TC, LDL-C and triglycerides (25%, 38% and 32% lower, respectively; P<0.0001) compared to control individuals, whereas HDL-C was increased (10% higher; P = 0.0136). Frequency of the common alleles, ε2, ε3 and ε4, was similar (P = 0.3568) between controls (n = 108) and patients (n = 84), implying that APOE genotype did not affect susceptibility to the advanced stage of schistosomiasis. Nevertheless, while patient TC and LDL-C levels were significantly reduced for each allele (except TC in ε2 patients), changes in HDL-C and triglycerides were noted only for the less common ε2 and ε4 alleles. The most striking finding, however, was that accepted regulation of plasma lipid levels by APOE genotype was disrupted by schistosomiasis. Thus, while ε2 controls had higher TC and LDL-C than ε3 carriers, these parameters were lower in ε2 versus ε3 patients. Similarly, the inverse relationship of TG levels in controls (ε2>ε3>ε4) was absent in patients (ε2 or ε4>ε3), and the increase in HDL-C of ε2 or ε4 patients compared to ε3 patients was not seen in the control groups.

Conclusion/Significance

We confirm that human schistosomiasis causes dyslipidemia and report for the first time that certain changes in plasma lipid and lipoprotein levels depend on APOE gene polymorphism. Importantly, we also concluded that S. mansoni disrupts the expected regulation of plasma lipids by the different ApoE isoforms. This finding suggests ways to identify new metabolic pathways affected by schistosomiasis and also potential molecular targets to treat associated morbidities.

Biochemical and nutritional evaluation of patients with visceral leishmaniasis before and after treatment with leishmanicidal drugs

INTRODUCTION

Visceral leishmaniasis (VL) is caused by the intracellular protozoan Leishmania donovani complex. VL may be asymptomatic or progressive and is characterized by fever, anemia, weight loss and the enlargement of the spleen and liver. The nutritional status of the patients with VL is a major determinant of the progression, severity and mortality of the disease, as it affects the clinical progression of the disease. Changes in lipoproteins and plasma proteins may have major impacts in the host during infection. Thus, our goal was evaluate the serum total cholesterol, high-density lipoprotein (HDL), low-density lipoprotein (LDL), triglycerides, glucose, albumin, globulin and total protein levels, as well as the body composition, of VL patients before and after treatment.

METHODS

Nutritional evaluation was performed using the bioelectrical impedance analysis (BIA) to assess body composition. Biochemical data on the serum total cholesterol, HDL, LDL, triglycerides, glucose, albumin, globulin and total protein were collected from the medical charts of the patients.

RESULTS

BIA indicated that both pre-treatment and post-treatment patients exhibited decreased phase angles compared to the controls, which is indicative of disease. Prior to treatment, the patients exhibited lower levels of total body water compared to the controls. Regarding the biochemical evaluation, patients with active VL exhibited lower levels of total cholesterol, HDL, LDL and albumin and higher triglyceride levels compared to patients after treatment and the controls. Treatment increased the levels of albumin and lipoproteins and decreased the triglyceride levels.

CONCLUSIONS

Our results suggest that patients with active VL present biochemical and nutritional changes that are reversed by treatment.

Light and confocal microscopic observations of adult Schistosoma mansoni from mice fed on a high-fat diet

The morphological aspects of Schistosoma mansoni adult worms recovered from albino mice fed on a cholesterol-rich diet compared to mice fed on a standard chow were investigated. After feeding on their respective diets for over a period of 5 months, mice were subcutaneously infected with c. 50 S. mansoni cercariae/mouse. Blood samples were obtained 1 day prior to experimental infections and 63 days later, when mice were euthanized by jugular section (hypovolaemic shock). Total cholesterol (TC) levels were determined. Recovered worms were stained with hydrochloric carmine, and preserved as whole-mounts for examination by bright-field and laser confocal microscopy. The infected mice fed on high-fat chow showed higher levels of serum lipoproteins than the infected mice fed on standard chow, except for very-low-density lipoprotein cholesterol (VLDL-c) and triglycerides (TG). In this experiment, worms from mice fed on a high-fat chow showed a greater percentage of morphological differentiation regarding supernumerary testes, seminal vesicle, and seminal receptacle. In mice of this group, the rate of oocyte laying in the ovary was much higher than in control females. The present results suggest that cholesterol could be actively involved in the modulation of cell signalling and reproduction, because the lobes contained fully developed oocytes in variable amounts, different from control males. The data presented here are the first to report the role of a cholesterol-rich diet affecting the development of S. mansoni worms.

Microarray analysis of gene expression induced by sexual contact in Schistosoma mansoni

Background

The parasitic trematode Schistosoma mansoni is one of the major causative agents of Schistosomiasis, a disease that affects approximately 200 million people, mostly in developing countries. Since much of the pathology is associated with eggs laid by the female worm, understanding the mechanisms involved in oogenesis and sexual maturation is an important step towards the discovery of new targets for effective drug therapy. It is known that the adult female worm only develops fully in the presence of a male worm and that the rates of oviposition and maturation of eggs are significantly increased by mating. In order to study gene transcripts associated with sexual maturation and oviposition, we compared the gene expression profiles of sexually mature and immature parasites using DNA microarrays.

Results

For each experiment, three amplified RNA microarray hybridizations and their dye swaps were analyzed. Our results show that 265 transcripts are differentially expressed in adult females and 53 in adult males when mature and immature worms are compared. Of the genes differentially expressed, 55% are expressed at higher levels in paired females while the remaining 45% are more expressed in unpaired ones and 56.6% are expressed at higher levels in paired male worms while the remaining 43.4% are more expressed in immature parasites. Real-time RT-PCR analysis validated the microarray results. Several new maturation associated transcripts were identified. Genes that were up-regulated in single-sex females were mostly related to energy generation (i.e. carbohydrate and protein metabolism, generation of precursor metabolites and energy, cellular catabolism, and organelle organization and biogenesis) while genes that were down-regulated related to RNA metabolism, reactive oxygen species metabolism, electron transport, organelle organization and biogenesis and protein biosynthesis.

Conclusion

Our results confirm previous observations related to gene expression induced by sexual maturation in female schistosome worms. They also increase the list of S. mansoni maturation associated transcripts considerably, therefore opening new and exciting avenues for the study of the conjugal biology and development of new drugs against schistosomes.

Long-term feeding a high-fat diet causes histological and parasitological effects on murine schistosomiasis mansoni outcome

This study investigated whether long-term feeding a high-fat diet (HFC) has an effect on schistosomiasis mansoni outcome compared to standard chow diet (SC). Swiss Webster female mice (3 wk old) fed each diet over 5 months, and then were infected with 50 Schistosoma mansoni cercariae. Their nutritional status was assessed by monitoring growth rates twice a week and measuring serum levels of lipoproteins. Mice were euthanised 63 days after infection. Parasitological and liver histological analyses were performed. The levels of TC, HDL-C and LDL-C, fecal and tissue schistosome eggs were statistically different (p<0.05) between groups. Livers from HFC mice showed exudative, exudative/exudative-productive, exudative-productive and productive granulomas, some degree of hepatic steatosis and focal necrosis. Mice fed normal-chow did not present productive granulomas and hepatic steatosis. The morphometric evaluation of hepatic granulomas did not reach statistical significance (p>0.05) between diets assayed. The high-fat diet for long-term produces effects on schistosomiasis mansoni outcome.