Highly tunable thiosulfonates as a novel class of cysteine protease inhibitors with anti-parasitic activity against Schistosoma mansoni

The development of a new class of cysteine protease inhibitors utilising the thiosulfonate moiety as an SH specific electrophile is described. This moiety has been introduced into suitable amino acid derived building blocks, which were incorporated into peptidic sequences leading to very potent i.e. sub micromolar inhibitors of the cysteine protease papain in the same range as the vinyl sulfone based inhibitor K11777. Therefore, their inhibitory effect on Schistosoma mansoni, a human blood parasite, that expresses several cysteine proteases, was evaluated. The homophenylalanine side chain containing compounds 27 - 30 and especially 36 showed promising activities compared with K11777 and warrant further investigations of these peptidic thiosulfonate inhibitors as new potential anti-parasitic compounds

Longitudinal Monitoring of Lactate in Hospitalized and Ambulatory COVID-19 Patients.

Hypoxemia is readily detectable by assessing SpO2 levels, and these are important in optimizing COVID-19 patient management. Hyperlactatemia is a marker of tissue hypoxia, particularly in patients with increased oxygen requirement and microvascular obstruction. We monitored peripheral venous lactate concentrations in hospitalized patients with moderate to severe COVID-19 (n = 18) and in mild ambulatory COVID-19 patients in home quarantine (n = 16). Whole blood lactate decreased significantly during the clinical course and recovery in hospitalized patients (P = 0.008). The blood lactate levels were significantly higher in hospitalized patients than ambulatory patients (day 1: hospitalized versus ambulatory patients P = 0.002; day 28: hospitalized versus ambulatory patients P = < 0.0001). Elevated lactate levels may be helpful in risk stratification, and serial monitoring of lactate may prove useful in the care of hospitalized COVID-19 patients

A review on innovative optical devices for the diagnosis of human soil-transmitted helminthiasis and schistosomiasis: from research and development to commercialization

Diagnosis of soil-transmitted helminth (STH) and schistosome infections relies largely on conventional microscopy which has limited sensitivity, requires highly trained personnel and is error-prone. Rapid advances in miniaturization of optical systems, sensors and proces-sors have enhanced research and development of digital and automated microscopes suitable for the detection of these diseases in resource-limited settings. While some studies have reported proof-of-principle results, others have evaluated the performance of working proto-types in field settings. The extensive commercialization of these innovative devices has, how-ever, not yet been achieved. This review provides an overview of recent publications (2010- 2022) on innovative field applicable optical devices which can be used for the diagnosis of STH and schistosome infections. Using an adapted technology readiness level (TRL) scale tak -ing into account the WHO target product profile (TPP) for these diseases, the developmental stages of the devices were ranked to determine the readiness for practical applications in field settings. From the reviewed 18 articles, 19 innovative optical devices were identified and ranked. Almost all of the devices (85%) were ranked with a TRL score below 8 indicating that, most of the devices are not ready for commercialization and field use. The potential lim-itations of these innovative devices were discussed. We believe that the outcome of this review can guide the end-to-end development of automated digital microscopes aligned with the WHO TPP for the diagnosis of STH and schistosome infections in resource-limited settings.Host-parasite interactio

Calmodulin-like proteins localized to the conoid regulate motility and cell invasion by Toxoplasma gondii

Toxoplasma gondii contains an expanded number of calmodulin (CaM)-like proteins whose functions are poorly understood. Using a combination of CRISPR/Cas9-mediated gene editing and a plant-like auxin-induced degron (AID) system, we examined the roles of three apically localized CaMs. CaM1 and CaM2 were individually dispensable, but loss of both resulted in a synthetic lethal phenotype. CaM3 was refractory to deletion, suggesting it is essential. Consistent with this prediction auxin-induced degradation of CaM3 blocked growth. Phenotypic analysis revealed that all three CaMs contribute to parasite motility, invasion, and egress from host cells, and that they act downstream of microneme and rhoptry secretion. Super-resolution microscopy localized all three CaMs to the conoid where they overlap with myosin H (MyoH), a motor protein that is required for invasion. Biotinylation using BirA fusions with the CaMs labeled a number of apical proteins including MyoH and its light chain MLC7, suggesting they may interact. Consistent with this hypothesis, disruption of MyoH led to degradation of CaM3, or redistribution of CaM1 and CaM2. Collectively, our findings suggest these CaMs may interact with MyoH to control motility and cell invasion

Hemolysis Is Associated with Low Reticulocyte Production Index and Predicts Blood Transfusion in Severe Malarial Anemia

Background: Falciparum Malaria, an infectious disease caused by the apicomplexan parasite Plasmodium falciparum, is among the leading causes of death and morbidity attributable to infectious diseases worldwide. In Gabon, Central Africa, one out of four inpatients have severe malarial anemia (SMA), a life-threatening complication if left untreated. Emerging drug resistant parasites might aggravate the situation. This case control study investigates biomarkers of enhanced hemolysis in hospitalized children with either SMA or mild malaria (MM). Methods and Findings: Ninety-one children were included, thereof 39 SMA patients. Strict inclusion criteria were chosen to exclude other causes of anemia. At diagnosis, erythrophagocytosis (a direct marker for extravascular hemolysis, EVH) was enhanced in SMA compared to MM patients (5.0 arbitrary units (AU) (interquartile range (IR): 2.2–9.6) vs. 2.1 AU (IR: 1.3–3.9), p<0.01). Furthermore, indirect markers for EVH, (i.e. serum neopterin levels, spleen size enlargement and monocyte pigment) were significantly increased in SMA patients. Markers for erythrocyte ageing, such as CD35 (complement receptor 1), CD55 (decay acceleration factor) and phosphatidylserine exposure (annexin-V-binding) were investigated by flow cytometry. In SMA patients, levels of CD35 and CD55 on the red blood cell surface were decreased and erythrocyte removal markers were increased when compared to MM or reconvalescent patients. Additionally, intravascular hemolysis (IVH) was quantified using several indirect markers (LDH, alpha-HBDH, haptoglobin and hemopexin), which all showed elevated IVH in SMA. The presence of both IVH and EVH predicted the need for blood transfusion during antimalarial treatment (odds ratio 61.5, 95% confidence interval (CI): 8.9–427). Interestingly, this subpopulation is characterized by a significantly lowered reticulocyte production index (RPI, p<0.05). Conclusions: Our results show the multifactorial pathophysiology of SMA, whereby EVH and IVH play a particularly important role. We propose a model where removal of infected and non-infected erythrocytes of all ages (including reticulocytes) by EVH and IVH is a main mechanism of SMA. Further studies are underway to investigate the mechanism and extent of reticulocyte removal to identify possible interventions to reduce the risk of SMA development

A call to caution when hydroxychloroquine is given to elderly COVID-19 patients.

INTRODUCTION: Hydroxychloroquine use in COVID-19 patients was widespread and uncontrolled until recently. Patients vulnerable to severe COVID-19 are at risk for hydroxychloroquine interactions with comorbidities and co-medications contributing to detrimental, including fatal adverse treatment effects. METHODS: This is a retrospective survey of health conditions and co-medications of COVID-19 patients who were pre-screened for enrolment into a randomized, double-blind, placebo-controlled hydroxychloroquine multicenter trial. RESULTS: Our survey involved 305 patients (median age 71 (IQR: 59-81) years). The majority of patients (N = 279, 92%) considered for inclusion into the clinical trial were not eligible mainly due to safety concerns caused by health conditions or co-medications. Most common were QT prolonging drugs (N = 188, 62%) and hematologic/hemato-oncologic diseases (N = 39, 13%) which prohibited the administration of hydroxychloroquine in our clinical trial. Additionally, 165 (54%) patients had health conditions and 167 (55%) were on co-medications that did not prohibit hydroxychloroquine treatment but had a risk of adverse interactions with hydroxychloroquine. Most common were diabetes (N = 86, 28%), renal insufficiency (N = 69, 23%) and heart failure (N = 58, 19%). CONCLUSION: The majority of hospitalized COVID-19 patients had health conditions or took co-medications precluding safe treatment with hydroxychloroquine. Therefore, especially in elderly, hydroxychloroquine should be administered with extreme caution and only in clinical trials

Boromycin has Rapid-Onset Antibiotic Activity Against Asexual and Sexual Blood Stages of Plasmodium falciparum

Boromycin is a boron-containing macrolide antibiotic produced by Streptomyces antibioticus with potent activity against certain viruses, Gram-positive bacteria and protozoan parasites. Most antimalarial antibiotics affect plasmodial organelles of prokaryotic origin and have a relatively slow onset of action. They are used for malaria prophylaxis and for the treatment of malaria when combined to a fast-acting drug. Despite the success of artemisinin combination therapies, the current gold standard treatment, new alternatives are constantly needed due to the ability of malaria parasites to become resistant to almost all drugs that are in heavy clinical use. In vitro antiplasmodial activity screens of tetracyclines (omadacycline, sarecycline, methacycline, demeclocycline, lymecycline, meclocycline), macrolides (oleandomycin, boromycin, josamycin, troleandomycin), and control drugs (chloroquine, clindamycin, doxycycline, minocycline, eravacycline) revealed boromycin as highly potent against Plasmodium falciparum and the zoonotic Plasmodium knowlesi. In contrast to tetracyclines, boromycin rapidly killed asexual stages of both Plasmodium species already at low concentrations (~ 1 nM) including multidrug resistant P. falciparum strains (Dd2, K1, 7G8). In addition, boromycin was active against P. falciparum stage V gametocytes at a low nanomolar range (IC(50): 8.5 ± 3.6 nM). Assessment of the mode of action excluded the apicoplast as the main target. Although there was an ionophoric activity on potassium channels, the effect was too low to explain the drug´s antiplasmodial activity. Boromycin is a promising antimalarial candidate with activity against multiple life cycle stages of the parasite