Exploring Geometrical, Electronic and Spectroscopic Properties of 2-Nitroimidazole-Based Radiopharmaceuticals via Computational Chemistry Methods.

Tumor hypoxia plays an important role in the clinical management and treatment planning of various cancers. The use of 2-nitroimidazole-based radiopharmaceuticals has been the most successful for positron emission tomography (PET) and single photon emission computed tomography (SPECT) imaging probes, offering noninvasive means to assess tumor hypoxia. In this study we performed detailed computational investigations of the most used compounds for PET imaging, focusing on those derived from 2-nitroimidazole: fluoromisonidazole (FMISO), fluoroazomycin arabinoside (FAZA), fluoroetanidazole (FETA), fluoroerythronitroimidazole (FETNIM) and 2-(2-nitroimidazol-1-yl)-N-(2,2,3,3,3-pentafluoropropyl)acetamide (EF5). Conformational analysis, structural parameters, vibrational IR and Raman properties (within both harmonic and anharmonic approximations), as well as the NMR shielding tensors and spin-spin coupling constants were obtained by density functional theory (DFT) calculations and then correlated with experimental findings, where available. Furthermore, time-dependent DFT computations reveal insight into the excited states of the compounds. Our results predict a significant change in the conformational landscape of most of the investigated compounds when transitioning from the gas phase to aqueous solution. According to computational data, the 2-nitroimidazole moiety determines to a large extent the spectroscopic properties of its derivatives. Due to the limited structural information available in the current literature for the investigated compounds, the findings presented herein deepen the current understanding of the electronic structures of these five radiopharmaceuticals.

Triple combination dry powder formulation of pretomanid, moxifloxacin, and pyrazinamide for treatment of multidrug-resistant tuberculosis.

Both latent and multidrug-resistant tuberculosis (TB) have been causing significant concern worldwide. A novel drug, pretomanid (PA-824), has shown a potent bactericidal effect against both active and latent forms of Mycobacterium tuberculosis (MTb) and a synergistic effect when combined with pyrazinamide and moxifloxacin. This study aimed to develop triple combination spray dried inhalable formulations composed of antitubercular drugs, pretomanid, moxifloxacin, and pyrazinamide (1:2:8 w/w/w), alone (PaMP) and in combination with an aerosolization enhancer, L-leucine (20 % w/w, PaMPL). The formulation PaMPL consisted of hollow, spherical, dimpled particles (<5 µm) and showed good aerosolization behaviour with a fine particle fraction of 70 %. Solid-state characterization of formulations with and without L-leucine confirmed the amorphous nature of moxifloxacin and pretomanid and the crystalline nature of pyrazinamide with polymorphic transformation after the spray drying process. Further, the X-ray photoelectron spectroscopic analysis revealed the predominant surface composition of L-leucine on PaMPL dry powder particles. The dose-response cytotoxicity results showed pyrazinamide and moxifloxacin were non-toxic in both A549 and Calu-3 cell lines up to 150 µg/mL. However, the cell viability gradually decreased to 50 % when the pretomanid concentration increased to 150 µg/mL. The in vitro efficacy studies demonstrated that the triple combination formulation had more prominent antibacterial activity with a minimum inhibitory concentration (MIC) of 1 µg/mL against the MTb H37Rv strain as compared to individual drugs. In conclusion, the triple combination of pretomanid, moxifloxacin, and pyrazinamide as an inhalable dry powder formulation will potentially improve treatment efficacy with fewer systemic side effects in patients suffering from latent and multidrug-resistant TB.

HIF-1α induced by hypoxic condition regulates Treg/Th17 axis polarization in chronic immune thrombocytopenia.

Immune thrombocytopenia (ITP) is an acquired immune disorder characterized by increased platelet destruction and reduced platelet (Plt) production. Hypoxia-inducible factor-1α (HIF-1α) have regulatory effects on Treg/Th17 axis balance and may represent relevant factors in the pathogenesis of ITP. Treg/Th17 ratio, serum levels and gene expression were investigated in new diagnosed ITP (NITP) and chronic ITP (CITP). The Treg/Th17 ratio obviously decreased in CITP (P = 0.001). The ratio of Treg/Th17 was correlated with the level of HIF-1α level both in mRNA (r = 0.49, P < 0.0001) and serum level (r = 0.50, P < 0.0001). However, none statistical upregulation of HIF-1α was observed in CITP. In vitro, There was significant polarization difference of Treg/Th17 axis (P = 0.042) and Foxp3-MFI/IL17-MFI (P = 0.0003) in hypoxic condition between NITP and CITP. These findings suggest that HIF-1α induced by hypoxia plays a crucial role in the chronicity of ITP by mediating the imbalance of the Treg/Th17 axis.

Colonic epithelial hypoxia remains constant during the progression of diabetes in male UC Davis type 2 diabetes mellitus rats.

INTRODUCTION: Colonocyte oxidation of bacterial-derived butyrate has been reported to maintain synergistic obligate anaerobe populations by reducing colonocyte oxygen levels; however, it is not known whether this process is disrupted during the progression of type 2 diabetes. Our aim was to determine whether diabetes influences colonocyte oxygen levels in the University of California Davis type 2 diabetes mellitus (UCD-T2DM) rat model. RESEARCH DESIGN AND METHODS: Age-matched male UCD-T2DM rats (174±4 days) prior to the onset of diabetes (PD, n=15), within 1 month post-onset (RD, n=12), and 3 months post-onset (D3M, n=12) were included in this study. Rats were administered an intraperitoneal injection of pimonidazole (60 mg/kg body weight) 1 hour prior to euthanasia and tissue collection to estimate colonic oxygen levels. Colon tissue was fixed in 10% formalin, embedded in paraffin, and processed for immunohistochemical detection of pimonidazole. The colonic microbiome was assessed by 16S gene rRNA amplicon sequencing and content of short-chain fatty acids was measured by liquid chromatography-mass spectrometry. RESULTS: HbA1c % increased linearly across the PD (5.9±0.1), RD (7.6±0.4), and D3M (11.5±0.6) groups, confirming the progression of diabetes in this cohort. D3M rats had a 2.5% increase in known facultative anaerobes, Escherichia-Shigella, and Streptococcus (false discovery rate <0.05) genera in colon contents. The intensity of pimonidazole staining of colonic epithelia did not differ across groups (p=0.37). Colon content concentrations of acetate and propionate also did not differ across UCD-T2DM groups; however, colonic butyric acid levels were higher in D3M rats relative to PD rats (p<0.01). CONCLUSIONS: The advancement of diabetes in UCD-T2DM rats was associated with an increase in facultative anaerobes; however, this was not explained by changes in colonocyte oxygen levels. The mechanisms underlying shifts in gut microbe populations associated with the progression of diabetes in the UCD-T2DM rat model remain to be identified.

Hypoxia-activated selectivity-improved anti-PKM2 antibody combined with prodrug TH-302 for potentiated targeting therapy in hepatocellular carcinoma.

Background: Hypoxia induces hepatocellular carcinoma (HCC) malignancies; yet it also offers treatment opportunities, exemplified by developing hypoxia-activated prodrugs (HAPs). Although HAP TH-302 combined with therapeutic antibody (Ab) has synergistic effects, the clinical benefits are limited by the on-target off-tumor toxicity of Ab. Here, we sought to develop a hypoxia-activated anti-M2 splice isoform of pyruvate kinase (PKM2) Ab combined with TH-302 for potentiated targeting therapy. Methods: Codon-optimized and hypoxia-activation strategies were used to develop H103 Ab-azo-PEG5k (HAP103) Ab. Hypoxia-activated HAP103 Ab was characterized, and hypoxia-dependent antitumor and immune activities were evaluated. Selective imaging and targeting therapy with HAP103 Ab were assessed in HCC-xenografted mouse models. Targeting selectivity, systemic toxicity, and synergistic therapeutic efficacy of HAP103 Ab with TH-302 were evaluated. Results: Human full-length H103 Ab was produced in a large-scale bioreactor. Azobenzene (azo)-linked PEG5k conjugation endowed HAP103 Ab with hypoxia-activated targeting features. Conditional HAP103 Ab effectively inhibited HCC cell growth, enhanced apoptosis, and induced antibody-dependent cellular cytotoxicity (ADCC) and complement-dependent cytotoxicity (CDC) functions. Analysis of HCC-xenografted mouse models showed that HAP103 Ab selectively targeted hypoxic HCC tissues and induced potent tumor-inhibitory activity either alone or in combination with TH-302. Besides the synergistic effects, HAP103 Ab had negligible side effects when compared to parent H103 Ab. Conclusion: The hypoxia-activated anti-PKM2 Ab safely confers a strong inhibitory effect on HCC with improved selectivity. This provides a promising strategy to overcome the on-target off-tumor toxicity of Ab therapeutics; and highlights an advanced approach to precisely kill HCC in combination with HAP TH-302.

Shell-dependent photofragmentation dynamics of a heavy-atom-containing bifunctional nitroimidazole radiosensitizer.

Radiation therapy uses ionizing radiation to break chemical bonds in cancer cells, thereby causing DNA damage and leading to cell death. The therapeutic effectiveness can be further increased by making the tumor cells more sensitive to radiation. Here, we investigate the role of the initial halogen atom core hole on the photofragmentation dynamics of 2-bromo-5-iodo-4-nitroimidazole, a potential bifunctional radiosensitizer. Bromine and iodine atoms were included in the molecule to increase the photoionization cross-section of the radiosensitizer at higher photon energies. The fragmentation dynamics of the molecule was studied experimentally in the gas phase using photoelectron-photoion-photoion coincidence spectroscopy and computationally using Born-Oppenheimer molecular dynamics. We observed significant changes between shallow core (I 4d, Br 3d) and deep core (I 3d) ionization in fragment formation and their kinetic energies. Despite the fact, that the ions ejected after deep core ionization have higher kinetic energies, we show that in a cellular environment, the ion spread is not much larger, keeping the damage well-localized.

Exploring novel pyrazole-nitroimidazole hybrids: Synthesis and antiprotozoal activity against the human pathogen trichomonas vaginalis.

Trichomoniasis, a prevalent sexually transmitted infection (STI) caused by the protozoan Trichomonas vaginalis, has gained increased significance globally. Its relevance has grown in recent years due to its association with a heightened risk of acquiring and transmitting the human immunodeficiency virus (HIV) and other STIs. In addition, many publications have revealed a potential link between trichomoniasis and certain cancers. Metronidazole (MTZ), a nitroimidazole compound developed over 50 years ago, remains the first-choice drug for treatment. However, reports of genotoxicity and side effects underscore the necessity for new compounds to address this pressing global health concern. In this study, we synthesized ten pyrazole-nitroimidazoles 1(a-j) and 4-nitro-1-(hydroxyethyl)-1H-imidazole 2, an analog of metronidazole (MTZ), and assessed their trichomonacidal and cytotoxic effects. All compounds 1(a-j) and 2 exhibited IC50 values ≤ 20 µM and ≤ 41 µM, after 24 h and 48 h, respectively. Compounds 1d (IC50 5.3 µM), 1e (IC50 4.8 µM), and 1i (IC50 5.2 µM) exhibited potencies equivalent to MTZ (IC50 4.9 µM), the reference drug, after 24 h. Notably, compound 1i showed high anti-trichomonas activity after 24 h (IC50 5.2 µM) and 48 h (IC50 2.1 µM). Additionally, all compounds demonstrated either non-cytotoxic to HeLa cells (CC50 > 100 µM) or low cytotoxicity (CC50 between 69 and 100 µM). These findings suggest that pyrazole-nitroimidazole derivatives represent a promising heterocyclic system, serving as a potential lead for further optimization in trichomoniasis chemotherapy.

Drug-resistant tuberculosis is a global cause of concern.

The number of patients with drug-resistant tuberculosis (DR-TB) is increasing worldwide. This review summarises the global epidemiology of DR-TB and current treatment challenges. Luckily, novel regimens comprising bedaquiline, pretomanid, linezolid, and moxifloxacin have seemingly mitigated the global threat posed by DR-TB. However, emerging resistance against bedaquiline and pretomanid, among other factors, persists as ongoing concerns in the global fight against DR-TB. While the new regimens are groundbreaking, the sustained development of novel drugs targeting the most resistant forms of tuberculosis is of utmost importance for future efforts against DR-TB.

Melanoma on congenital melanocytic nevi.

Among nevus-associated melanomas, which overall account for 20%-30% of all melanomas, those arising specifically in congenital melanocytic nevi are infrequent, but can be disproportionately frequent in childhood and adolescence. Congenital melanocytic nevi (CMNi) are common benign melanocytic tumors that are present at birth or become apparent in early childhood. They are classified based on the projected adult size. Small and medium-sized CMNi are frequent, whereas large/giant CMNi (over 20 cm in diameter) are rare, but can be associated with high morbidity due to marked aesthetic impairment and the risk of neurocutaneous syndrome or melanoma development. In this setting, melanomas can appear in early childhood and are very aggressive, while the risk of small-medium CMNi of developing melanoma is low and similar to non-congenital melanocytic nevi. Histologically, most melanomas on CMNi initiate their growth at the epidermal-dermal junction, but in large/giant CMNi they can develop entirely in the dermis, in deeper tissues, or in extracutaneous sites (especially in the central nervous system). Most CMNi harbour an NRAS mutation, but other genes are rarely involved, and gene translocations have recently been described. However, no prognostic implications have been associated with the CMN genotype. Melanomas developed on CMNi harbour additional molecular alterations to which the aggressive clinical course of these tumors has been attributed. This review covers the distinctive clinical and pathological aspects of melanomas on CMNi, and includes the epidemiology, etiopathogenesis, clinical and dermoscopic presentation, histological and molecular characteristics, as well as tumour behaviour.

Development of a self-microemulsifying drug delivery system to deliver delamanid via a pressurized metered dose inhaler for treatment of multi-drug resistant pulmonary tuberculosis.

Tuberculosis (TB) is a serious health issue that contributes to millions of deaths throughout the world and increases the threat of serious pulmonary infections in patients with respiratory illness. Delamanid is a novel drug approved in 2014 to deal with multi-drug resistant TB (MDR-TB). Despite its high efficiency in TB treatment, delamanid poses delivery challenges due to poor water solubility leading to inadequate absorption upon oral administration. This study involves the development of novel formulation-based pressurized metered dose inhalers (pMDIs) containing self-microemulsifying mixtures of delamanid for efficient delivery to the lungs. To identify the appropriate self-microemulsifying formulations, ternary diagrams were plotted using different combinations of surfactant to co-surfactant ratios (1:1, 2:1, and 3:1). The combinations used Cremophor RH40, Poly Ethylene Glycol 400 (PEG 400), and peppermint oil, and those that showed the maximum microemulsion region and rapid and stable emulsification were selected for further characterization. The diluted self-microemulsifying mixtures underwent evaluation of dose uniformity, droplet size, zeta potential, and transmission electron microscopy. The selected formulations exhibited uniform delivery of the dose throughout the canister life, along with droplet sizes and zeta potentials that ranged from 24.74 to 88.99 nm and - 19.27 to - 10.00 mV, respectively. The aerosol performance of each self-microemulsifying drug delivery system (SMEDDS)-pMDI was assessed using the Next Generation Impactor, which indicated their capability to deliver the drug to the deeper areas of the lungs. In vitro cytotoxicity testing on A549 and NCI-H358 cells revealed no significant signs of toxicity up to a concentration of 1.56 µg/mL. The antimycobacterial activity of the formulations was evaluated against Mycobacterium bovis using flow cytometry analysis, which showed complete inhibition by day 5 with a minimum bactericidal concentration of 0.313 µg/mL. Moreover, the cellular uptake studies showed efficient delivery of the formulations inside macrophage cells, which indicated the potential for intracellular antimycobacterial activity. These findings demonstrated the potential of the Delamanid-SMEDDS-pMDI for efficient pulmonary delivery of delamanid to improve its effectiveness in the treatment of multi-drug resistant pulmonary TB.

Post-therapeutic cure criterion in chronic Chagas disease using Trypanosoma cruzi chimeric proteins.

Chagas disease (CD) is a neglected disease caused by Trypanosoma cruzi Chagas, 1909. Causative treatment can be achieved with two drugs: benznidazole or Nifurtimox. There are some gaps that hinder progress in eradicating the disease. There is no test that can efficiently assess cure control after treatment. Currently, the decline in anti-T. cruzi antibody titres is assessed with conventional serological tests, which can take years. However, the search for new markers of cure must continue to fill this gap. The present study aimed to evaluate the decline in serological titres using chimeric proteins after treatment with benznidazole in chronic patients diagnosed with CD. It was a prospective cross-sectional cohort study between 2000 and 2004 of T. cruzi-positive participants from the Añatuya region (Argentina) treated with benznidazole. Serum samples from ten patients were collected before treatment (day zero) and after the end of treatment (2, 3, 6, 12, 24 and 36 months). For the detection of anti-T. cruzi antibodies, an indirect ELISA was performed using two chimeric recombinant proteins (IBMP-8.1 and IBMP-8.4) as antigens. The changes in reactivity index within the groups before and after treatment were evaluated using the Friedman test. All participants experienced a decrease in serological titres after treatment with benznidazole, especially IBMP-8.1. However, due to the small number of samples and the short follow-up period, it is premature to conclude that this molecule serves as a criterion for sustained cure. Further studies are needed to validate tests based on these or other biomarkers to demonstrate parasitological cure.

Interaction between peripheral blood mononuclear cells and Trypanosoma cruzi-infected adipocytes: implications for treatment failure and induction of immunomodulatory mechanisms in adipose tissue.

Background/Introduction: Adipose tissue (AT) has been highlighted as a promising reservoir of infection for viruses, bacteria and parasites. Among them is Trypanosoma cruzi, which causes Chagas disease. The recommended treatment for the disease in Brazil is Benznidazole (BZ). However, its efficacy may vary according to the stage of the disease, geographical origin, age, immune background of the host and sensitivity of the strains to the drug. In this context, AT may act as an ally for the parasite survival and persistence in the host and a barrier for BZ action. Therefore, we investigated the immunomodulation of T. cruzi-infected human AT in the presence of peripheral blood mononuclear cells (PBMC) where BZ treatment was added. Methods: We performed indirect cultivation between T. cruzi-infected adipocytes, PBMC and the addition of BZ. After 72h of treatment, the supernatant was collected for cytokine, chemokine and adipokine assay. Infected adipocytes were removed to quantify T. cruzi DNA, and PBMC were removed for immunophenotyping. Results: Our findings showed elevated secretion of interleukin (IL)-6, IL-2 and monocyte chemoattractant protein-1 (MCP-1/CCL2) in the AT+PBMC condition compared to the other controls. In contrast, there was a decrease in tumor necrosis factor (TNF) and IL-8/CXCL-8 in the groups with AT. We also found high adipsin secretion in PBMC+AT+T compared to the treated condition (PBMC+AT+T+BZ). Likewise, the expression of CD80+ and HLA-DR+ in CD14+ cells decreased in the presence of T. cruzi. Discussion: Thus, our findings indicate that AT promotes up-regulation of inflammatory products such as IL-6, IL-2, and MCP-1/CCL2. However, adipogenic inducers may have triggered the downregulation of TNF and IL-8/CXCL8 through the peroxisome proliferator agonist gamma (PPAR-g) or receptor expression. On the other hand, the administration of BZ only managed to reduce inflammation in the microenvironment by decreasing adipsin in the infected culture conditions. Therefore, given the findings, we can see that AT is an ally of the parasite in evading the host's immune response and the pharmacological action of BZ.

In vitro evaluation of [3H]PI-2620 and structural derivatives in non-Alzheimer's tauopathies.

Alzheimer's disease (AD) and non-AD tauopathies such as chronic traumatic encephalopathy (CTE), progressive supranuclear palsy (PSP), and corticobasal degeneration (CBD) are characterized by the abnormal aggregation of three-repeat (3R) and/or four-repeat (4R) tau isoforms. Several tau-PET tracers have been applied for human imaging of AD and non-AD tauopathies including [18F]PI-2620. Our objective is to evaluate [3H]PI-2620 and two promising structural derivatives, [3H]PI-2014 and [3H]F-4, using in vitro saturation assays and competitive binding assays against new chemical entities based on this scaffold in human AD tissues for comparison with PSP, CBD and CTE tissues. Thin section autoradiography was employed to assess specific binding and distribution of [3H]PI-2620 and [3H]F-4 in fresh-frozen human post-mortem AD, PSP, CBD and CTE tissues. Immunohistochemistry was performed for phospho-tau (AT8) and 4R-tau (RD4). Homogenate filtration binding assays were performed for saturation analysis and competitive binding studies against [3H]PI-2620. All compounds bound with high affinity in AD tissue. In PSP tissue [3H]PI-2620 demonstrated the highest affinity (5.3 nM) and in CBD tissue [3H]F-4 bound with the highest affinity (9.4 nM). Over 40 fluorinated derivatives based on PI-2620 and F-4 were screened in AD and PSP tissue. Notably, compound 2 was the most potent derivative in PSP tissue (Ki = 7.3 nM). By autoradiography, [3H]PI-2620 and [3H]F-4 demonstrated positive signals similar in intensity in AD, PSP and CTE tissues that were displaced by homologous blockade. Binding of both radiotracers aligned with immunostaining for 4R-tau. This work demonstrates that [3H]PI-2620 and [3H]F-4 show promise for imaging 4R-tau aggregates in non-AD tauopathies. PI-2620 continues to serve as a structural scaffold for PET radiotracers with higher affinity for non-AD tau over AD tau.

Novel magnetic porous organic polymer containing amino and triazine bifunctional groups for efficient adsorption of nitroimidazoles.

In this paper, a novel magnetic hyper-crosslinked polymer with amino and triazine bifunctional groups (M-NH2-THCP) was developed. M-NH2-THCP has strong nitroimidazoles (NDZs) enrichment effect, and therefore it was used as an adsorbent to extract five NDZs from lake water, catfish and shrimp meat prior to HPLC. Polar interaction, π-π stacking interaction, hydrogen bond and Lewis acid-base interaction were attested to be the major adsorption mechanism. The method has a good linearity in the range of 0.1-100 ng mL-1 for lake water, 10-400 ng g-1 for catfish and shrimp muscle with R2 > 0.9964. The limits of detection of NDZs were 0.03-0.04 ng mL-1 for lake water, 1.0-2.0 ng g-1 for catfish and 2.0-2.5 ng g-1 for shrimp, which is superior to most reported method. The method recoveries were 87.6-119 %, and relative standard deviations were less than 8.7 %. M-NH2-THCP holds great application potential in pollutants enrichment, separation and removal.

Green synthesis of azo-linked porous organic polymer for enrichment of nitroimidazoles from water, shrimp and Basa fish.

Reliable monitoring of nitroimidazoles (NDZs) is of great significance to public health. Herein, an azo-linked porous organic polymer (Res-POPs) was prepared by green synthesis method using natural resveratrol as monomer for the first time. Using Res-POPs as sorbent, a facile method coupling solid-phase extraction with high performance liquid chromatography-diode array detection was developed for effective detecting NDZs. The method achieved good linearities (0.06 âˆ¼ 100 ng mL-1 for water, 1.8 âˆ¼ 200 ng g-1 for shrimp, and 1.5 âˆ¼ 200 ng g-1 for Basa fish) with determination coefficients above 0.995, low detection limits (0.02 âˆ¼ 0.05 ng mL-1, 0.60 âˆ¼ 1.00 ng g-1 and 0.50 âˆ¼ 0.90 ng g-1 for water, shrimp and Basa fish), high method recovery (85 %∼114 %) and relative standard deviations below 8.2 %. The results demonstrated the superiority and the promising potential of the established method for detection of NDZs compared with the reported method.

Multiple myeloma and Chagas disease: qPCR as a marker for preemptive antiparasitic therapy: a case reports series and review.

Multiple myeloma (MM) associated with Chagas disease is rarely described. This disease and its therapy suppress T cell and macrophage functions and increase regulatory T cell function, allowing the increase of parasitemia and the risk of Chagas Disease Reactivation (CDR). We aimed to analyze the role of conventional (cPCR) and quantitative Polymerase Chain Reaction (qPCR) for prospective monitoring of T. cruzi parasitemia, searching for markers of preemptive antiparasitic therapy in MM patients with Chagas disease. Moreover, we investigated the incidence and management of hematological diseases and CDR both inside and outside the transplant setting in the MEDLINE database. We found 293 studies and included 31 of them. Around 1.9-2.0% of patients with Chagas disease were reported in patients undergoing Stem Cell Transplantation. One case of CDR was described in eight cases of MM and Chagas disease. We monitored nine MM and Chagas disease patients, seven under Autologous Stem Cell Transplantation (ASCT), during 44.56±32.10 months (mean±SD) using parasitological methods, cPCR, and qPCR. From these patients, three had parasitemia. In the first, up to 256 par Eq/mL were detected, starting from 28 months after ASCT. The second patient dropped out and died soon after the detection of 161.0 par Eq/mL. The third patient had a positive blood culture. Benznidazole induced fast negativity in two cases; followed by notably lower levels in one of them. Increased T. cruzi parasitemia was related to the severity of the underlying disease. We recommend parasitemia monitoring by qPCR for early introduction of preemptive antiparasitic therapy to avoid CDR.

Bactericidal and sterilizing activity of novel regimens combining bedaquiline or TBAJ-587 with GSK2556286 and TBA-7371 in a mouse model of tuberculosis.

The combination of bedaquiline, pretomanid, and linezolid (BPaL) has become a preferred regimen for treating multidrug- and extensively drug-resistant tuberculosis (TB). However, treatment-limiting toxicities of linezolid and reports of emerging bedaquiline and pretomanid resistance necessitate efforts to develop new short-course oral regimens. We recently found that the addition of GSK2556286 increases the bactericidal and sterilizing activity of BPa-containing regimens in a well-established BALB/c mouse model of tuberculosis. Here, we used this model to evaluate the potential of new regimens combining bedaquiline or the more potent diarylquinoline TBAJ-587 with GSK2556286 and the DprE1 inhibitor TBA-7371, all of which are currently in early-phase clinical trials. We found the combination of bedaquiline, GSK2556286, and TBA-7371 to be more active than the first-line regimen and nearly as effective as BPaL in terms of bactericidal and sterilizing activity. In addition, we found that GSK2556286 and TBA-7371 were as effective as pretomanid and the novel oxazolidinone TBI-223 when either drug pair was combined with TBAJ-587 and that the addition of GSK2556286 increased the bactericidal activity of the TBAJ-587, pretomanid, and TBI-223 combination. We conclude that GSK2556286 and TBA-7371 have the potential to replace pretomanid, an oxazolidinone, or both components, in combination with bedaquiline or TBAJ-587.

Refined understanding of the impact of the Mycobacterium tuberculosis complex diversity on the intrinsic susceptibility to pretomanid.

Previous work reported unprecedented differences in the intrinsic in vitro susceptibility of the Mycobacterium tuberculosis complex (MTBC) to pretomanid (Pa) using the Mycobacteria Growth Indicator Tube (MGIT) system. We tested 125 phylogenetically diverse strains from all known MTBC lineages (1-9) without known Pa resistance mutations and four strains with known resistance mutations as controls. This confirmed that MTBC, unlike most bacteria-antimicrobial combinations, displayed substantial differences in the intrinsic susceptibility relative to the technical variation of Pa MIC testing. This was also the case for the Middlebrook 7H11 (7H11) medium, demonstrating that these differences were not specific to MGIT. Notably, lineage 1 was confirmed to have intrinsically elevated MICs compared with lineages 2, 3, 4, and 7 (L2-4/7), underlining the urgent need for WHO to publish its decision of whether lineage 1 should be deemed treatable by BPaL(M), the now preferred all-oral regimen for treating rifampin-resistant tuberculosis. Lineages 5 and 6, which are most frequent in West Africa, responded differently to Pa, with lineage 5 being more similar to L2-4/7 and lineage 6 being more susceptible. More data are needed to determine whether 7H11 MICs are systematically lower than those in MGIT. IMPORTANCE: This study confirmed that the Mycobacterium tuberculosis complex lineage 1, responsible for 28% of global tuberculosis cases, is less susceptible to pretomanid (Pa). It also refined the understanding of the intrinsic susceptibilities of lineages 5 and 6, most frequent in West Africa, and lineages 8 and 9. Regulators must review whether these in vitro differences affect the clinical efficacy of the WHO-recommended BPaL(M) regimen and set breakpoints for antimicrobial susceptibility testing accordingly. Notably, regulators should provide detailed justifications for their decisions to facilitate public scrutiny.

A systematic efficacy analysis of tuberculosis treatment with BPaL-containing regimens using a multiscale modeling approach.

Tuberculosis (TB) is a life-threatening infectious disease. The standard treatment is up to 90% effective; however, it requires the administration of four antibiotics (isoniazid, rifampicin, pyrazinamide, and ethambutol [HRZE]) over long time periods. This harsh treatment process causes adherence issues for patients because of the long treatment times and a myriad of adverse effects. Therefore, the World Health Organization has focused goals of shortening standard treatment regimens for TB in their End TB Strategy efforts, which aim to reduce TB-related deaths by 95% by 2035. For this purpose, many novel and promising combination antibiotics are being explored that have recently been discovered, such as the bedaquiline, pretomanid, and linezolid (BPaL) regimen. As a result, testing the number of possible combinations with all possible novel regimens is beyond the limit of experimental resources. In this study, we present a unique framework that uses a primate granuloma modeling approach to screen many combination regimens that are currently under clinical and experimental exploration and assesses their efficacies to inform future studies. We tested well-studied regimens such as HRZE and BPaL to evaluate the validity and accuracy of our framework. We also simulated additional promising combination regimens that have not been sufficiently studied clinically or experimentally, and we provide a pipeline for regimen ranking based on their efficacies in granulomas. Furthermore, we showed a correlation between simulation rankings and new marmoset data rankings, providing evidence for the credibility of our framework. This framework can be adapted to any TB regimen and can rank any number of single or combination regimens.

Quantitative PCR as a marker for preemptive therapy and its role in therapeutic control in Trypanosoma cruzi/HIV coinfection.

BACKGROUND: Trypanosoma cruzi and HIV coinfection can evolve with depression of cellular immunity and increased parasitemia. We applied quantitative PCR (qPCR) as a marker for preemptive antiparasitic treatment to avoid fatal Chagas disease reactivation and analyzed the outcome of treated cases. METHODOLOGY: This mixed cross-sectional and longitudinal study included 171 Chagas disease patients, 60 coinfected with HIV. Of these 60 patients, ten showed Chagas disease reactivation, confirmed by parasites identified in the blood, cerebrospinal fluid, or tissues, 12 exhibited high parasitemia without reactivation, and 38 had low parasitemia and no reactivation. RESULTS: We showed, for the first time, the success of the timely introduction of benznidazole in the non-reactivated group with high levels of parasitemia detected by qPCR and the absence of parasites in reactivated cases with at least 58 days of benznidazole. All HIV+ patients with or without reactivation had a 4.0-5.1 higher chance of having parasitemia than HIV seronegative cases. A positive correlation was found between parasites and viral loads. Remarkably, treated T. cruzi/HIV-coinfected patients had 77.3% conversion from positive to negative parasitemia compared to 19.1% of untreated patients. Additionally, untreated patients showed ~13.6 times higher Odds Ratio of having positive parasitemia in the follow-up period compared with treated patients. Treated and untreated patients showed no differences regarding the evolution of Chagas disease. The main factors associated with all-cause mortality were higher parasitemia, lower CD4 counts/µL, higher viral load, and absence of antiretroviral therapy. CONCLUSION: We recommend qPCR prospective monitoring of T. cruzi parasitemia in HIV+ coinfected patients and point out the value of pre-emptive therapy for those with high parasitemia. In parallel, early antiretroviral therapy introduction is advisable, aiming at viral load control, immune response restoration, and increasing survival. We also suggest an early antiparasitic treatment for all coinfected patients, followed by effectiveness analysis alongside antiretroviral therapy.