Molecular targets in cerebral malaria for developing novel therapeutic strategies.

Cerebral malaria (CM) is the severe neurological complication associated with Plasmodium falciparum infection. In clinical settings CM is predominantly characterized by fever, epileptic seizures, and asexual forms of parasite on blood smears, coma and even death. Cognitive impairment in the children and adults even after survival is one of the striking consequences of CM. Poor diagnosis often leads to inappropriate malaria therapy which in turn progress into a severe form of disease. Activation of multiple cell death pathways such as Inflammation, oxidative stress, apoptosis and disruption of blood brain barrier (BBB) plays critical role in the pathogenesis of CM and secondary brain damage. Thus, understanding such mechanisms of neuronal cell death might help to identify potential molecular targets for CM. Mitigation strategies for mortality rate and long-term cognitive deficits caused by existing anti-malarial drugs still remains a valid research question to ask. In this review, we discuss in detail about critical neuronal cell death mechanisms and the overall significance of adjunctive therapy with recent trends, which provides better insight towards establishing newer therapeutic strategies for CM.

Ameliorating the in vivo antimalarial efficacy of artemether using nanostructured lipid carriers.

Cerebral malaria (CM) is a fatal neurological complication of Plasmodium falciparum infection that affects children (below five years old) in sub-Saharan Africa and adults in South-East Asia each year having the fatality rate of 10-25%. The survivors of CM also have high risk of long term neurological or cognitive deficits. The objective of the present investigation was to develop optimised nanostructured lipid carriers (NLCs) of artemether (ARM) for enhanced anti-malarial efficacy of ARM. NLCs of ARM were prepared by a combination of high speed homogenisation (HSH) and probe sonication techniques. Preliminary solubility studies for ARM showed highest solubility in trimyristin (solid lipid), capmul MCM NF (liquid lipid) and polysorbate 80 (surfactant). Trimyristin and capmul showed superior miscibility at a ratio of 70:30.The optimised NLC formulation has the particle size (PS) of: 48.59 ± 3.67 nm, zeta potential (ZP) of: -32 ± 1.63 mV and entrapment efficiency (EE) of: 91 ± 3.62%. In vitro cell line (human embryonic kidney fibroblast cell line (HEK 293 T)) cytotoxicity studies showed that prepared formulation was non-toxic. The results of in vivo studies in CM induced mice prevented the recrudescence of parasite after administration of NLCs of ARM. Additionally, NLCs of ARM showed better parasite clearance, higher survival (60%) in comparison to ARM solution (40%). Also it was observed that lesser entrapment of Evans blue stain (prepared in PBS as solution) in the NLCs of ARM treated brains of C57BL/6 mice than ARM solution treated mice. Hence NLCs of ARM may be a better alternative for improving therapeutic efficacy than ARM solution.

Dysregulation of LIMK-1/cofilin-1 pathway: A possible basis for alteration of neuronal morphology in experimental cerebral malaria.

OBJECTIVE: Loss of cognition even after survival is the salient feature of cerebral malaria (CM). Currently, the fate of neuronal morphology is not studied at the ultrastructural level in CM. Recent studies suggest that maintenance of neuronal morphology and dendritic spine density (actin dynamics in particular) are essential for proper cognitive function. LIMK-1/cofilin-1 signaling pathway is known to be involved in the maintenance of actin dynamics through regulation of cofilin-1, and in executing learning and memory functions. METHODS: Using an experimental mouse model, we analyzed the behavioral parameters of asymptomatic mice with CM by performing a rapid murine coma and behavior scale experiment. We performed Golgi-Cox staining to assess neuronal morphology, dendritic spine density, and arborization in brain cortex subjected to Plasmodium berghei ANKA infection compared to asymptomatic, anemic, and control groups. We studied the neural gene expression pattern of LIMK-1, cofilin-1, and ß-actin in all the experimental groups by semiquantitative and quantitative polymerase chain reaction followed by immunoblotting and immunofluorescence. RESULTS: We observed significant loss of dendritic spine density, abnormal spine morphology, reduced dendritic arborization, and extensive dendritic varicosities in the cortical neurons of CM-infected brain. Furthermore, these observations correlated with diminished protein levels of LIMK-1, cofilin-1, phospho-cofilin-1, and ß-actin in the whole brain lysates as well as formation of actin-cofilin rods in the brain sections of symptomatic mice with CM. INTERPRETATION: Overall, our findings suggest that the altered neuronal morphology and dysregulation of LIMK-1/cofilin-1 pathway could affect the cognitive outcome after experimental CM. Therefore, this study could help to establish newer therapeutic strategies addressing long-term cognitive impairment after CM. Ann Neurol 2017;82:429-443.

Malaria treatment using novel nano-based drug delivery systems.

We reside in an era of technological innovation and advancement despite which infectious diseases like malaria remain to be one of the greatest threats to the humans. Mortality rate caused by malaria disease is a huge concern in the twenty-first century. Multiple drug resistance and nonspecific drug targeting of the most widely used drugs are the main reasons/drawbacks behind the failure in malarial therapy. Dose-related toxicity because of high doses is also a major concern. Therefore, to overcome these problems nano-based drug delivery systems are being developed to facilitate site-specific or target-based drug delivery and hence minimizing the development of resistance progress and dose-dependent toxicity issues. In this review, we discuss about the shortcomings in treating malaria and how nano-based drug delivery systems can help in curtailing the infectious disease malaria.