Global host metabolic response to Plasmodium vivax infection: a 1H NMR based urinary metabonomic study

<p>Abstract</p> <p>Background</p> <p><it>Plasmodium vivax </it>is responsible for the majority of malarial infection in the Indian subcontinent. This species of the parasite is generally believed to cause a relatively benign form of the disease. However, recent reports from different parts of the world indicate that vivax malaria can also have severe manifestation. Host response to the parasite invasion is thought to be an important factor in determining the severity of manifestation. In this paper, attempt was made to determine the host metabolic response associated with <it>P. vivax </it>infection by means of NMR spectroscopy-based metabonomic techniques in an attempt to better understand the disease pathology.</p> <p>Methods</p> <p>NMR spectroscopy of urine samples from <it>P. vivax-</it>infected patients, healthy individuals and non-malarial fever patients were carried out followed by multivariate statistical analysis. Two data analysis techniques were employed, namely, Principal Component Analysis [PCA] and Orthogonal Projection to Latent Structure Discriminant Analysis [OPLS-DA]. Several NMR signals from the urinary metabolites were further selected for univariate comparison among the classes.</p> <p>Results</p> <p>The urine metabolic profiles of <it>P. vivax-</it>infected patients were distinct from those of healthy individuals as well as of non-malarial fever patients. A highly predictive model was constructed from urine profile of malarial and non-malarial fever patients. Several metabolites were found to be varying significantly across these cohorts. Urinary ornithine seems to have the potential to be used as biomarkers of vivax malaria. An increasing trend in pipecolic acid was also observed. The results suggest impairment in the functioning of liver as well as impairment in urea cycle.</p> <p>Conclusions</p> <p>The results open up a possibility of non-invasive analysis and diagnosis of <it>P. vivax </it>using urine metabolic profile. Distinct variations in certain metabolites were recorded, and amongst these, ornithine may have the potential of being used as biomarker of malaria. Pipecolic acid also showed increasing trend in the malaria patient compared to the other groups.</p

Multifaceted Role of Heme during Severe Plasmodium falciparum Infections in India

Several immunomodulatory factors are involved in malaria pathogenesis. Among them, heme has been shown to play a role in the pathophysiology of severe malaria in rodents, but its role in human severe malaria remains unclear. Circulating levels of total heme and its main scavenger, hemopexin, along with cytokine/chemokine levels and biological parameters, including hemoglobin and creatinine levels, as well as transaminase activities, were measured in the plasma of 237 Plasmodium falciparum-infected patients living in the state of Odisha, India, where malaria is endemic. All patients were categorized into well-defined groups of mild malaria, cerebral malaria (CM), or severe noncerebral malaria, which included acute renal failure (ARF) and hepatopathy. Our results show a significant increase in total plasma heme levels with malaria severity, especially for CM and malarial ARF. Spearman rank correlation and canonical correlation analyses have shown a correlation between total heme, hemopexin, interleukin-10, tumor necrosis factor alpha, gamma interferon-induced protein 10 (IP-10), and monocyte chemotactic protein 1 (MCP-1) levels. In addition, canonical correlations revealed that heme, along with IP-10, was associated with the CM pathophysiology, whereas both IP-10 and MCP-1 together with heme discriminated ARF. Altogether, our data indicate that heme, in association with cytokines and chemokines, is involved in the pathophysiology of both CM and ARF but through different mechanisms.Indo-French Centre for the Promotion of Advanced Research, Associated International Laboratory Systems (LIA; CNRS), Immunology and Genetics of Infectious Diseases (SIGID), Department of Biotechnology from the Ministry of Science and Technology of India (DBT), Tata Institute of Fundamental Research (TIFR) (intramural funds), Université Lille (doctoral contract), IFCPAR (Raman-Charpak award), College Doctoral Lille Nord de France (AAP n10 award), Fondation des Treille, Conseil Régional du Nord-Pas de Calais

Malaria vaccine: a current perspective

The observation that inactivated Plasmodium sporozoites could protect against malaria is about a hundred years old. However, systematic demonstration of protection using irradiated sporozoites occurred in the nineteen-sixties, providing the impetus for the development of a malaria vaccine. In 1983, the circumsporozoite protein (CSP), a major sporozoite surface antigen, became the first Plasmodium gene to be cloned, and a CSP-based vaccine appeared imminent. Today, 25 years later, we are still without an effective malaria vaccine, despite considerable information regarding the genomics and proteomics of the malaria parasites. Although clinical immunity to malaria has been well-documented in adults living in malaria endemic areas, our understanding of the host-immune responses operating in such malaria immune persons remains poor, and limits the development of immune control of the disease. Currently, several antigen and adjuvant combinations have entered clinical trials, in which efficacy against experimental sporozoite challenge and/or exposure to natural infection is evaluated. This review collates information on the recent status of the field. Unresolved challenges facing the development of a malaria vaccine are also discussed

Design and in vivo pharmacodynamic evaluation of nanostructured lipid carriers for parenteral delivery of artemether: nanoject

The objective of the present investigation was to explore the potential of nanostructured lipid carriers (NLC) for the intravenous delivery of artemether (ARM), a poorly water-soluble antimalarial agent. The NLC of ARM (Nanoject) were formulated by employing a microemulsion template technique. The NLC were evaluated for particle size, encapsulation efficiency, in vitro drug release and in vitro hemolysis. The antimalarial activity of the Nanoject and conventional ARM injectable formulation was evaluated in Plasmodium berghei infected mice. The average particle size of Nanoject was 63±28 nm and the encapsulation efficiency was found to be 30±2%. The Nanoject released ARM in a sustained manner. In vitro haemolytic studies showed that Nanoject had lower haemolytic potential (~13%) as compared to all the components when studied individually. Nanoject showed significantly higher (P &lt; 0.005) antimalarial activity as compared to the marketed injectable formulation. The antimalarial activity of Nanoject lasted for a longer duration (more than 20 days) indicating that Nanoject may be long-circulating in vivo. Nanoject showed significantly higher survival rate (60%) even after 31 days as compared to marketed formulation which showed 0% survival (100% mortality). This clearly indicates that Nanoject offers several advantages over the currently marketed oily intramuscular formulation (Larither®)

Solid microemulsion preconcentrate (NanOsorb) of artemether for effective treatment of malaria

A microemulsion preconcentrate was formulated on the basis of solubility of artemether (ARM) in the various oily phases and surfactants and phase diagrams. Various solid adsorbents were evaluated for their ability yield solid microemulsion preconcentrates (NanOsorb-ARM). NanOsorb-ARM on dilution yielded microemulsion with average globule size of 183 nm and polydispersity index of 0.498 when determined using photon correlation spectroscopy. The antimalarial activity of NanOsorb-ARM, ARM solution and marketed ARM formulation (Larither®) was evaluated in Plasmodium berghei infected mice as per Peter's four day protocol. The acute lethal dose and the subacute toxicity of NanOsorb-ARM were determined as per the method suggested in Organization for Economic Cooperation and Development (OECD) guidelines. The NanOsorb-ARM exhibited significantly higher antimalarial activity (P &lt; 0.05) as compared to the marketed formulation of artemether (Larither®). Surprisingly, placebo NanOsorb also showed significantly higher antimalarial activity as compared to Larither® indicating that excipients used for the formulation of NanOsorb may have antimalarial activity. Subacute toxicity studies demonstrated that NanOsorb-ARM is comparatively safer than artemether oily solution with respect to survival, gross pathology, hematology and serum biochemistry in mice of both the genders

Development of SMEDDS using natural lipophile: application to β-Artemether delivery

The objective of the present investigation was to formulate self-microemulsifying drug delivery systems (SMEDDS) using a novel, indigenous natural lipophile (N-LCT) as an oily phase. SMEDDS based on N-LCT and commercially available modified oil (Capryol 90) were formulated and their application in improving the delivery of a lipophilic anti-malarial drug, β-Artemether (BAM) was also evaluated. BAM-loaded SMEDDS were characterized with respect to mean globule size and in vitro drug release profile in comparison to the marketed formulation (Larither®). Comparative in vivo anti-malarial performance of the developed SMEDDS was evaluated against the (Larither®) in Swiss male mice infected with lethal ANKA strain of Plasmodium berghei. The parameters studied were percent parasitemia, activity against time and animal survival period. Both the BAM-SMEDDS showed excellent self-microemulsification efficiency and released &gt;98% of the drug in just 15 min whereas (Larither®) showed only 46% drug release at the end of 1 h. The mean globule size for optimized BAM-SMEDDS was &lt;100 nm. The anti-malarial studies revealed that BAM-SMEDDS resulted in significant improvement in the anti-malarial activity (P &lt; 0.05) as compared to that of (Larither®) and BAM solubilized in the oily phases and surfactant. The developed SMEDDS highlight safety for use and potential applications of indigenous natural lipophile in the development of novel colloidal drug carriers

Evidence of IL-17, IP-10, and IL-10 involvement in multiple-organ dysfunction and IL-17 pathway in acute renal failure associated to Plasmodium falciparum malaria.

International audienceBACKGROUND: Plasmodium falciparum malaria in India is characterized by high rates of severe disease, with multiple organ dysfunction (MOD)-mainly associated with acute renal failure (ARF)-and increased mortality. The objective of this study is to identify cytokine signatures differentiating severe malaria patients with MOD, cerebral malaria (CM), and cerebral malaria with MOD (CM-MOD) in India. We have previously shown that two cytokines clusters differentiated CM from mild malaria in Maharashtra. Hence, we also aimed to determine if these cytokines could discriminate malaria subphenotypes in Odisha.METHODS: P. falciparum malaria patients from the SCB Medical College Cuttack in the Odisha state in India were enrolled along with three sets of controls: healthy individuals, patients with sepsis and encephalitis (n = 222). We determined plasma concentrations of pro- and anti-inflammatory cytokines and chemokines for all individuals using a multiplex assay. We then used an ensemble of statistical analytical methods to ascertain whether particular sets of cytokines/chemokines were predictors of severity or signatures of a disease category.RESULTS: Of the 26 cytokines/chemokines tested, 19 increased significantly during malaria and clearly distinguished malaria patients from controls, as well as sepsis and encephalitis patients. High amounts of IL-17, IP-10, and IL-10 predicted MOD, decreased IL-17 and MIP-1α segregated CM-MOD from MOD, and increased IL-12p40 differentiated CM from CM-MOD. Most severe malaria patients with ARF exhibited high levels of IL-17.CONCLUSION: We report distinct differences in cytokine production correlating with malarial disease severity in Odisha and Maharashtra populations in India. We show that CM, CM-MOD and MOD are clearly distinct malaria-associated pathologies. High amounts of IL-17, IP-10, and IL-10 were predictors of MOD; decreased IL-17 and MIP-1α separated CM-MOD from MOD; and increased IL-12p40 differentiated CM from CM-MOD. Data also suggest that the IL-17 pathway may contribute to malaria pathogenesis via different regulatory mechanisms and may represent an interesting target to mitigate the pathological processes in malaria-associated ARF

Age-Dependent Sex Bias in Clinical Malarial Disease in Hypoendemic Regions

<div><h3>Background and Objectives</h3><p>Experimental models show a male bias in murine malaria; however, extant literature on biases in human clinical malaria is inconclusive. Studies in hyperendemic areas document an absence of sexual dimorphism in clinical malaria. Data on sex bias in clinical malaria in hypoendemic areas is ambiguous—some reports note a male bias but do not investigate the role of differential mosquito exposure in that bias. Moreover, these studies do not examine whether the bias is age related. This study investigates whether clinical malaria in hypoendemic regions exhibits a sex bias and whether this bias is age-dependent. We also consider the role of vector exposure in this bias.</p> <h3>Methods</h3><p>Retrospective passive clinical malaria datasets (2002–2007) and active surveillance datasets (2000–2009) were captured for the hypoendemic Mumbai region in Western India. To validate findings, passive retrospective data was captured from a primary malaria clinic (2006–2007) in hypoendemic Rourkela (Eastern India). Data was normalized by determining percent slide-positivity rates (SPRs) for males and females, and parasite-positivity distributions were established across age groups. The Mann–Whitney test, Wilcoxon Signed Rank test, and Chi-square analysis were used to determine statistical significances.</p> <h3>Results</h3><p>In both the Mumbai and Rourkela regions, clinical malaria exhibited an adult male bias (p<0.01). A sex bias was not observed in children aged ≤10. Post-puberty, male SPRs were significantly greater than females SPRs (p<0.01). This adult male bias was observed for both vivax and falciparum clinical disease. Analysis of active surveillance data did not reveal an age or sex bias in the frequency of parasite positivity.</p> <h3>Conclusion</h3><p>This study demonstrates an age-dependent sex bias in clinical malaria in hypoendemic regions and enhanced incidence of clinical malaria in males following puberty. Possible roles of sex hormones, vector exposure, co-infections, and other factors in this enhanced susceptibility are discussed.</p> </div