Plasmodium transmission blocking activities of Vernonia amygdalina extracts and isolated compounds

BACKGROUND: Medicinal plants are a validated source for discovery of new leads and standardized herbal medicines. The aim of this study was to assess the activity of Vernonia amygdalina leaf extracts and isolated compounds against gametocytes and sporogonic stages of Plasmodium berghei and to validate the findings on field isolates of Plasmodium falciparum. METHODS: Aqueous (Ver-H2O) and ethanolic (Ver-EtOH) leaf extracts were tested in vivo for activity against sexual and asexual blood stage P. berghei parasites. In vivo transmission blocking effects of Ver-EtOH and Ver-H2O were estimated by assessing P. berghei oocyst prevalence and density in Anopheles stephensi mosquitoes. Activity targeting early sporogonic stages (ESS), namely gametes, zygotes and ookinetes was assessed in vitro using P. berghei CTRPp.GFP strain. Bioassay guided fractionation was performed to characterize V. amygdalina fractions and molecules for anti-ESS activity. Fractions active against ESS of the murine parasite were tested for ex vivo transmission blocking activity on P. falciparum field isolates. Cytotoxic effects of extracts and isolated compounds vernolide and vernodalol were evaluated on the human cell lines HCT116 and EA.hy926. RESULTS: Ver-H2O reduced the P. berghei macrogametocyte density in mice by about 50% and Ver-EtOH reduced P. berghei oocyst prevalence and density by 27 and 90%, respectively, in An. stephensi mosquitoes. Ver-EtOH inhibited almost completely (>90%) ESS development in vitro at 50 μg/mL. At this concentration, four fractions obtained from the ethylacetate phase of the methanol extract displayed inhibitory activity >90% against ESS. Three tested fractions were also found active against field isolates of the human parasite P. falciparum, reducing oocyst prevalence in Anopheles coluzzii mosquitoes to one-half and oocyst density to one-fourth of controls. The molecules and fractions displayed considerable cytotoxicity on the two tested cell-lines. CONCLUSIONS: Vernonia amygdalina leaves contain molecules affecting multiple stages of Plasmodium, evidencing its potential for drug discovery. Chemical modification of the identified hit molecules, in particular vernodalol, could generate a library of druggable sesquiterpene lactones. The development of a multistage phytomedicine designed as preventive treatment to complement existing malaria control tools appears a challenging but feasible goal

Sector-specific development and policy vulnerability in the Philippines

Ministry of Education, Singapore under its Academic Research Funding Tier

Disease-Modifying Therapies and Coronavirus Disease 2019 Severity in Multiple Sclerosis

Objective: This study was undertaken to assess the impact of immunosuppressive and immunomodulatory therapies on the severity of coronavirus disease 2019 (COVID-19) in people with multiple sclerosis (PwMS). Methods: We retrospectively collected data of PwMS with suspected or confirmed COVID-19. All the patients had complete follow-up to death or recovery. Severe COVID-19 was defined by a 3-level variable: mild disease not requiring hospitalization versus pneumonia or hospitalization versus intensive care unit (ICU) admission or death. We evaluated baseline characteristics and MS therapies associated with severe COVID-19 by multivariate and propensity score (PS)-weighted ordinal logistic models. Sensitivity analyses were run to confirm the results. Results: Of 844 PwMS with suspected (n = 565) or confirmed (n = 279) COVID-19, 13 (1.54%) died; 11 of them were in a progressive MS phase, and 8 were without any therapy. Thirty-eight (4.5%) were admitted to an ICU; 99 (11.7%) had radiologically documented pneumonia; 96 (11.4%) were hospitalized. After adjusting for region, age, sex, progressive MS course, Expanded Disability Status Scale, disease duration, body mass index, comorbidities, and recent methylprednisolone use, therapy with an anti-CD20 agent (ocrelizumab or rituximab) was significantly associated (odds ratio [OR] = 2.37, 95% confidence interval [CI] = 1.18-4.74, p = 0.015) with increased risk of severe COVID-19. Recent use (<1 month) of methylprednisolone was also associated with a worse outcome (OR = 5.24, 95% CI = 2.20-12.53, p = 0.001). Results were confirmed by the PS-weighted analysis and by all the sensitivity analyses. Interpretation: This study showed an acceptable level of safety of therapies with a broad array of mechanisms of action. However, some specific elements of risk emerged. These will need to be considered while the COVID-19 pandemic persists

COVID-19 Severity in Multiple Sclerosis: Putting Data Into Context

Background and objectives: It is unclear how multiple sclerosis (MS) affects the severity of COVID-19. The aim of this study is to compare COVID-19-related outcomes collected in an Italian cohort of patients with MS with the outcomes expected in the age- and sex-matched Italian population. Methods: Hospitalization, intensive care unit (ICU) admission, and death after COVID-19 diagnosis of 1,362 patients with MS were compared with the age- and sex-matched Italian population in a retrospective observational case-cohort study with population-based control. The observed vs the expected events were compared in the whole MS cohort and in different subgroups (higher risk: Expanded Disability Status Scale [EDSS] score > 3 or at least 1 comorbidity, lower risk: EDSS score ≤ 3 and no comorbidities) by the χ2 test, and the risk excess was quantified by risk ratios (RRs). Results: The risk of severe events was about twice the risk in the age- and sex-matched Italian population: RR = 2.12 for hospitalization (p < 0.001), RR = 2.19 for ICU admission (p < 0.001), and RR = 2.43 for death (p < 0.001). The excess of risk was confined to the higher-risk group (n = 553). In lower-risk patients (n = 809), the rate of events was close to that of the Italian age- and sex-matched population (RR = 1.12 for hospitalization, RR = 1.52 for ICU admission, and RR = 1.19 for death). In the lower-risk group, an increased hospitalization risk was detected in patients on anti-CD20 (RR = 3.03, p = 0.005), whereas a decrease was detected in patients on interferon (0 observed vs 4 expected events, p = 0.04). Discussion: Overall, the MS cohort had a risk of severe events that is twice the risk than the age- and sex-matched Italian population. This excess of risk is mainly explained by the EDSS score and comorbidities, whereas a residual increase of hospitalization risk was observed in patients on anti-CD20 therapies and a decrease in people on interferon

DMTs and Covid-19 severity in MS: a pooled analysis from Italy and France

We evaluated the effect of DMTs on Covid-19 severity in patients with MS, with a pooled-analysis of two large cohorts from Italy and France. The association of baseline characteristics and DMTs with Covid-19 severity was assessed by multivariate ordinal-logistic models and pooled by a fixed-effect meta-analysis. 1066 patients with MS from Italy and 721 from France were included. In the multivariate model, anti-CD20 therapies were significantly associated (OR = 2.05, 95%CI = 1.39–3.02, p < 0.001) with Covid-19 severity, whereas interferon indicated a decreased risk (OR = 0.42, 95%CI = 0.18–0.99, p = 0.047). This pooled-analysis confirms an increased risk of severe Covid-19 in patients on anti-CD20 therapies and supports the protective role of interferon

Fatigue in multiple sclerosis: The contribution of resting-state functional connectivity reorganization

Objectives: To investigate resting-state functional connectivity (RS-FC) of the default-mode network (DMN) and of sensorimotor network (SMN) network in relapsing remitting (RR) multiple sclerosis (MS) patients with fatigue (F) and without fatigue(NF). Methods: In all, 59 RRMS patients and 29 healthy controls (HC) underwent magnetic resonance imaging (MRI) protocol including resting-state fMRI (RS-fMRI). Functional connectivity of the DMN and SMN was evaluated by independent component analysis (ICA). A linear regression analysis was performed to explore whether fatigue was mainly driven by changes observed in the DMN or in the SMN. Regional gray matter atrophy was assessed by voxel-based morphometry (VBM). Results: Compared to HC, F-MS patients showed a stronger RS-FC in the posterior cingulate cortex (PCC) and a reduced RS-FC in the anterior cingulated cortex (ACC) of the DMN. F-MS patients, compared to NF-MS patients, revealed (1) an increased RS-FC in the PCC and a reduced RS-FC in the ACC of the DMN and (2) an increased RS-FC in the primary motor cortex and in the supplementary motor cortex of the SMN. The regression analysis suggested that fatigue is mainly driven by RS-FC changes of the DMN. Conclusions: Fatigue in RRMS is mainly associated to a functional rearrangement of non-motor RS networks

Malaria transmission blocking activity of sesquiterpene lactones from Vernonia amygdalina

Background: Most of the currently available anti-malarial drugs act on asexual stages of the Plasmodium parasite and have limited impact on the sexual stages to block transmission. Search for drugs active against transmissible stages imperative for the development of transmission blocking interventions. This study aimed to assess whether Vernonia amygdalina, a plant used traditionally to treat malaria fever, contains secondary metabolites interfering with the development of early sporogonic stages (ESS): gamete, zygote formation and/or ookinete maturation. Methods: Plasmodium berghei CTRPp.GFP was used to determine in vitro activity of fractions and isolated molecules against ESS. Gametocytemic blood from BALB/c mice was incubated in microplates with the test substances. Zygote and ookinete formation was scored after 40h of incubation under the fluorescent microscope (400x). The fractions, found active on P. berghei, were then examined on P. falciparum field isolates. Gametocytemic blood from volunteers was supplemented with fractions (at 100 ppm) and membrane fed to Anopheles coluzzii mosquitoes. A week later, mosquito midguts were dissected and examined for oocysts. Results: Organic fractions from the methanol extract of V. amygdalina leaves proved to be strongly active against ESS of P. berghei. Fraction 11 (eluted with n-hexane:ethylacetate 1:1 and 7:13) and fraction 13 (eluted with ethylacetate) suppressed ESS development by 98- 100% at a concentration of 50 ppm . In the experiments with P. falciparum field isolates, control mosquitoes displayed an oocyst prevalence ranging from 30 to 50%, whereas the oocyst prevalence in mosquitoes membrane fed with gametocytemic blood treated with fraction 11 and 13 at 100 ppm ranged from 0 to 32% and 0 to 8%, respectively. The oocyst density among oocyst-positive mosquitoes varied from 3.5 to 4.2 per mosquito in controls, compare to 1.8 to 2.4 and 1.3 to 1.8 in fraction 11 and 13, respectively. Subsequent chemical analysis revealed sesquiterpenes vernolide and vernodalol to be the major components of fraction 11 and 13, respectively. The isolated molecules confirmed their effects on P. berghei ESS in vitro, with vernodalol displaying a relatively stronger inhibitory activity than vernolide on the transmissible stages. Conclusion: Vernolide and vernodalol rich fractions from V. amygdalina leaves hold promise for the development of medicines impacting on the transmissible stages of the malaria parasites

Safety of Natalizumab infusion in multiple sclerosis patients during active SARS-CoV-2 infection

: COVID-19 pandemic represented a challenge in the management of treatments for Multiple Sclerosis (MS), such as Natalizumab (NTZ). NTZ interferes with the homing of lymphocytes into the central nervous system, reducing immune surveillance against opportunistic infection. Although NTZ efficacy starts to decline 8 weeks after the last infusion, increasing the risk of disease reactivation, evidence is lacking on the safety of reinfusion during active SARS-CoV-2 infection. We report clinical outcomes of 18 pwMS receiving NTZ retreatment during confirmed SARS-CoV-2 infection. No worsening of infection or recovery delay was observed. Our data supports the safety of NTZ redosing in these circumstances