Blood pressure control and clinical outcomes after renal denervation through irrigated catheter radiofrequency ablation in patients with resistant hypertension: A case series with up to 10 years of follow-up

INTRODUCTION: The long-term efficacy of renal denervation (RDN) has not been extensively documented. AIM: To describe the long-term follow-up of patients after RDN. METHODS: We evaluated patients with resistant hypertension (RH) who underwent RDN with irrigated catheter from 2012 to 2014 at a single centre. Office blood pressure (BP) and 24-hour ambulatory BP were assessed. Clinical event (stroke, myocardial infarction, need for dialysis, or death from any cause), left ventricular mass index (LVMI), estimated glomerular filtration rate (eGFR), and urine albumin-to-creatinine ratio (uACR) were evaluated. RESULTS: The analysis included 20 individuals (age 51 ± 10 years, 75% female, ambulatory systolic BP [SBP] 168 ± 22 mmHg, ambulatory diastolic BP [DBP] 101 ± 19 mmHg, taking 7 [IQR: 6-8] antihypertensive medications). The median follow-up period was 8.5 (IQR: 5.6-9.4) years. Mean (± SD) changes from baseline were: -47 ± 41 mmHg for office SBP, -25 ± 20 mmHg for office DBP, -29 ± 26 mmHg for ambulatory SBP, and -15 ± 16 mmHg for ambulatory DBP. The number of antihypertensive drugs markedly decreased one month after RDN and a gradual upward trend was observed over time. A clinical event occurred in 9 (45%) participants. LVMI decreased from 152 ± 37 to 120 ± 31 g/m2 (p = 0.015), the eGFR declined from 88.9 ± 15.6 to 73.1 ± 24.2 mL/min/1.73 m2 (p = 0.034), and the uACR did not significantly change from baseline to follow-up. CONCLUSIONS: In this observational study of patients with uncontrolled RH, RDN with an irrigated catheter was associated with a sustained BP reduction for up to a decade. However, a potential waning efficacy was suggested by the increasing use of antihypertensive medications over time.

Systematic Review and Meta-Analysis of Second-Generation Sham-Controlled Randomized Trials of Renal Denervation Therapy for Patients with Hypertension.

INTRODUCTION: Renal denervation has been associated with substantial and sustained blood pressure reduction and is considered to serve as an alternative treatment for patients with resistant hypertension. However, the first published SHAM-controlled trial assessing RDN safety and efficacy showed no difference between groups. AIM: We aimed to perform a meta-analysis quantifying the magnitude of blood pressure decrease secondary to renal denervation in patients with resistant hypertension. METHODS: Databases were searched for RCTs that compared RDN therapy to SHAM procedure and reported the outcomes of (1) 24-hour ambulatory blood pressure; (2) Office systolic blood pressure; (3) Daytime systolic blood pressure; and (4) Night-time systolic blood pressure. Mean differences with 95% confidence intervals (CIs) were calculated using a random-effects model. Heterogeneity was examined with I² statistics. P values of < 0.05 were considered statistically significant. Statistical analyses were performed using RStudio 4.2.3. RESULTS: Nine studies and 1622 patients were included. The AMBP [MD -3.72 95%CI -5.44, -2.00 p < 0.001; I²=34%] and DSBP [MD -4.10 95%CI -5.84, -2.37 p < 0.001; I²=0%] were significantly reduced in the RDN arm. ODBP [MD -6.04 95%CI -11.31, -0.78 p = 0.024; I²=90%] and NSBP [MD -1.81 95%CI -3.90, 0.27 p = 0.08; I²=0%] did not reach a statistically significant difference between groups. CONCLUSION: Renal denervation demonstrates greater efficacy in reducing 24-hour ambulatory and daytime systolic blood pressure in patients diagnosed with resistant hypertension.

Diagnóstico de la tuberculosis y detección de la farmacorresistencia. Comunicación rápida

En esta comunicación rápida, la Organización Mundial de la Salud (OMS) presenta las actualizaciones sobre el diagnóstico de la tuberculosis (TB), con especial atención al uso concurrente de pruebas en adultos y adolescentes que viven con el VIH y en niños, incluidos los niños que viven con el VIH: el uso concurrente de la prueba molecular en muestras respiratorias y la LF-LAM en orina para el diagnóstico de la tuberculosis en adultos y adolescentes con VIH ha mejorado la precisión y moderado los costes en comparación con la prueba única el uso concurrente de pruebas moleculares en muestras respiratorias y heces para el diagnóstico de la tuberculosis en niños ha mejorado la precisión y los requisitos de costes moderados en comparación con las pruebas individuales.

Leishmania spp. genetic factors associated with cutaneous leishmaniasis antimony pentavalent drug resistance: a systematic review.

BACKGROUND: Leishmaniasis is a neglected zoonosis caused by parasites of Leishmania spp. The main drug used to treat cutaneous leishmaniasis (CL) is the antimoniate of meglumine. This drug, which has strong adverse and toxic effects, is usually administered intravenously, further complicating the difficult treatment. Factors such as Leishmania gene expression and genomic mutations appear to play a role in the development of drug resistance. OBJECTIVES: This systematic review summarises the results of the literature evaluating parasite genetic markers possibly associated with resistance to pentavalent antimony in CL. METHODS: This study followed PRISMA guidelines and included articles from PubMed, SciELO, and LILACS databases. Inclusion criteria were studies that (i) investigated mutations in the genome and/or changes in gene expression of Leishmania associated with treatment resistance; (ii) used antimony drugs in the therapy of CL; (iii) used naturally resistant strains isolated from patients. The Joanna Briggs Institute Critical Appraisal Checklist was used to assess article quality and risk of bias. FINDINGS: A total of 23 articles were selected, of which 18 investigated gene expression and nine genomic mutations. Of these 23 articles, four examined gene expression and genomic mutations in the same samples. Regarding gene expression, genes from the ABC transporter protein family, AQP1, MRPA, TDR1 and TRYR were most frequently associated with drug resistance. In one of the articles in which mutations were investigated, a mutation was found in HSP70 (T579A) and in three articles mutations were found in AQP1 (A516C, G562A and G700A). A limitation of this review is that in most of the included studies, parasites were isolated from cultured lesion samples and drug resistance was assessed using in vitro drug susceptibility testing. These approaches may not be ideal for accurate genetic evaluation and detection of treatment failure. MAIN CONCLUSIONS: The development of further studies to evaluate the genetic resistance factors of Leishmania spp. is necessary to elucidate the mechanisms of the parasite and improve patient treatment and infection control.

RaTexT®: a novel rapid tick exposure test for detecting acaricide resistance in Rhipicephalus microplus ticks in Brazil.

BACKGROUND: Acaricide resistance in cattle ticks is a significant concern in (sub)tropical regions, particularly Brazil. The Larval Packet Test (LPT) is the standard laboratory bioassay for resistance diagnosis, which requires triplicates of seven acaricidal dilutions plus controls to cover larval mortalities ranging between 0 and 100%. The value of the LPT lies in providing resistance ratios based on the ratio between the LC50 calculated with potentially resistant and susceptible ticks. However, LC50 ratios are difficult to translate into practical advice for farmers. Moreover, LPT requires laboratory facilities to maintain susceptible tick colonies, and it takes 6 weeks to obtain the larvae to be tested by LPT derived from engorged female ticks collected from cattle in the field. Our novel approach was twofold: first, we upgraded the LPT to the Resistance Intensity Test (RIT) by adopting the latest WHO guidelines for resistance detection in mosquitoes, which combines a 1 × recommended dose with 5 × and 10 × concentrated doses to reveal low, moderate and high resistance intensity, respectively. This reduced the number of test papers and tick larvae and, more importantly, provided relevant information on the resistance level. Our second innovative step was to abolish testing larvae entirely and expose partly engorged adult ticks to the same acaricidal doses immediately after removing them from cattle in the field. This resulted in the Rapid Tick exposure Test (RaTexT®), wherein partly engorged adult ticks were exposed to an acaricide-impregnated, specially designed matrix providing test results within 24 h. This approach directly compared resistance detection in tick larvae in the RIT with resistance in adult ticks in RaTexT®. METHODS: Laboratory validation was conducted in Brazil with resistant and susceptible colonies of Rhipicephalus microplus ticks. For field validation, adult R. microplus ticks collected from different cattle farms in Brazil were evaluated for resistance to RaTexT®, and the results regarding their larval progenies were compared with those for the RIT. Partly engorged adult ticks derived from cattle infested with laboratory and field strains of R. microplus were exposed to deltamethrin in RaTexT® containers, which contained six rows of four interconnected compartments, accommodating five to eight semi-engorged female ticks with a preferred size ranging between 5 and 8 mm. The corresponding larvae of each strain were exposed in the RIT to the same deltamethrin concentrations in filter papers. RESULTS: In RaTexT®, mortality in adult ticks from a resistant strain of R. microplus from Seropédica in Brazil was 38.4%, 54.2% and 75.0% at the 1 ×, 5 × and 10 × doses of deltamethrin, respectively. In RIT, mortality of larvae from the same resistant strain was 2.0%, 4.9% and 19.5% at 1 ×, 5 × and 10 × doses, respectively. The results of RaTexT® and RIT agreed since both tests identified a high level of resistance based on a cut-off of 90% mortality. In RaTexT®, mortality of adult ticks from a susceptible strain originating from Porto Alegre was 73.8%, 92.9% and 97.6% at the 1 ×, 5 × and 10 × doses, respectively. In RIT, mortality of larvae from the susceptible strain was 95.2%, 95.2% and 96.8% at the 1 ×, 5 × and 10 × doses, respectively. Interestingly, both tests identified a low number of unexpected resistant individuals in the susceptible strain since the mortality of neither larvae nor adults reached 100%. This effect remained unnoticed in the LPT, wherein a resistance ratio of 159.5 was found based on the LC50 of the resistant strain divided by the LC50 of the susceptible strain. Next, RaTexT® was compared with RIT using adult and larval ticks derived from three field strains of R. microplus in Brazil. RaTexT® detected high levels of resistance to deltamethrin in adult ticks in all strains, which was confirmed in larvae tested by the RIT. Both tests agreed on the same resistance level with significantly lower mortality rates in larvae than in adult ticks. CONCLUSIONS: RaTexT® is a novel rapid pen-site test for detecting acaricide resistance in adult livestock ticks. It potentially replaces laborious tests using larval ticks and provides results within 24 h relevant to acaricide resistance management of livestock ticks.

Anthelmintic resistance of gastrointestinal nematodes in cattle in Brazil and Argentina - current status and global perspectives.

This review outlines the current state of anthelmintic resistance (AHR) of gastrointestinal nematodes (GINs) among cattle in Argentina and Brazil, emphasizing the economic repercussions, animal health and welfare. The analysis explores factors associated with AHR and proposes a potential solution: the use of drug combinations. Both countries are grappling with a severe AHR scenario in cattle, having progressed through incipient, established, and advanced phases, leading to extreme cases of animal mortality due to ineffective control strategies. Genera such as Cooperia and Haemonchus have the highest reports of resistance, with Oesophagostomum radiatum also posing significant problems. While oral benzimidazoles and levamisole remain effective in most herds, moxidectin is entering an advanced resistance phase, and avermectins are increasingly deemed ineffective. The review explores the impact ofclimate, mixed grazing, animal movement and other husbandry practices, and the relationship between ectoparasite control and the emergence of resistant helminths. Notably, the discussion includes the strategic use of drug combinations as a valuable approach to address resistant GINs control in livestock, highlighting its significant potential to mitigate the challenges posed by AHR in the cattle industry of these countries.

Evaluation of aldosterone to direct renin ratio, low renin and related Phenotypes in Afro-Colombian patients with apparent treatment resistant hypertension.

Apparent resistant hypertension (aTRH) is a significant public health issue. Once low adherence to antihypertensive treatment has been ruled out and true resistant hypertension is diagnosed, aldosterone-direct-renin-ratio (ADRR) aids in the screening of an aldosterone-producing adenoma (APA) and primary aldosteronism (PA). Once PA and other secondary causes have been ruled out, the values of aldosterone and renin allow patients to be classified into phenotypes such as low renin hypertension (LRH), Liddle's-like (LLph), and primary hyperaldosteronism (PAph). These classifications could aid in the treatment decision-making process. However, optimal cut-off points for these classifications remain uncertain. This study aims to assess the prevalence of these phenotypes and the behavior of different cut-offs of the ADRR in an Afro-Colombian population with apparent resistant hypertension, as well to describe their sodium consumption. Afro-descendant individuals 18 years of age or older, diagnosed with resistant hypertension and attending to a primary care center in Colombia were recruited as volunteers. As part of the study, their plasma renin concentration (PRC) and plasma aldosterone concentration (PAC) were measured. The phenotypes were categorized into three groups based on multiple cut-off points from different authors: low renin and low aldosterone phenotype (LLph), low renin and high aldosterone phenotype (PAph), and high renin and high aldosterone phenotype, referred to as the renal phenotype (Rph). The prevalence of ADRR values exceeding the cut-off and phenotypes were calculated. A linear regression model was derived to assess the effect of sodium consumption with PAC, PRC and ADRR. A total of 88 patients with aTRH were included. Adherence to at least 3 antihypertensive medications was 62.5%. The median age was 56 years (IQR 48-60), 44% were female, and 20% had diabetes. The study found that the prevalence of ADRR values exceeding the cut-off ranged from 4.5 to 23%, while low-renin hypertension (LRH) varied from 15 to 74%, Rph was found in approximately 30 to 34% of patients, PAph in 30 to 51%, and the LLph in 15 to 41%, respectively, depending on the specific cut-off value by different authors. Notably, sodium consumption was associated with lower aldosterone (ß - 0.15, 95% CI [- 0.27, - 0.03]) and renin concentrations (ß - 0.75, 95% CI [- 1.5, - 0.02]), but ADRR showed no significant association with sodium consumption. There were no significant differences in prevalences between the groups taking < 3 vs ≥ 3 antihypertensive medications. Altered aldosterone-direct-renin-ratio, low renin hypertension, Liddle's-like, and primary hyperaldosteronism are prevalent phenotypes in patients within Afro-Colombian patients with apparent treatment-Resistant hypertension.

Acaricide effect of plants from the Brazilian savanna on a population of Rhipicephalus microplus with phenotypic resistance to cypermethrin and trichlorfon.

Rhipicephalus microplus is among the most important ectoparasites for livestock. The use of synthetic acaricides has raised some concerns due to the selection of tick populations that are resistant to acaricides and environmental contamination. Therefore, plant extracts have been used as alternatives for the treatment of animals infested with ticks. In this study, R. microplus populations from seven different dairy farms were collected and assessed for their resistance to the acaricides cypermethrin or trichlorfon. Larvae of the most resistant population were used in assays to evaluate the acaricide effect of leaf extracts from plants of the Brazilian savanna. The most active extracts were also tested against fully engorged females. Among seven tick populations, five and three showed resistance level ≥ III for cypermethrin or trichlorfon, respectively. The most resistant tick population was evaluated in mortality assays with the plants Piptadenia viridiflora, Annona crassiflora, Caryocar brasiliense, Ximenia americana, and Schinopsis brasilienses. The ethanolic extracts of C. brasiliense, X. americana and S. brasilienses showed higher larvicidal effects in comparison to the other extracts and cypermethrin. The ethanolic extract of X. americana showed 60.79 % efficacy against fully engorged females of the acaricide resistant tick strain. The ethanolic extracts of C. brasiliense, X. americana, and S. brasilienses showed peaks in HPLC-DAD, indicating the presence of tannins and flavonoids. Three of the plants showed promising results and should be explored in further studies to develop novel tools to control R. microplus in cattle.

Heme metabolism in Strigomonas culicis: Implications of H2O2 resistance induction and symbiont elimination.

Monoxenous trypanosomatid Strigomonas culicis harbors an endosymbiotic bacterium, which enables the protozoa to survive without heme supplementation. The impact of H2O2 resistance and symbiont elimination on intracellular heme and Fe2+ availability was analyzed through a comparison of WT strain with both WT H2O2-resistant (WTR) and aposymbiotic (Apo) protozoa. The relative quantification of the heme biosynthetic pathway through label-free parallel reaction monitoring targeted mass spectrometry revealed that H2O2 resistance does not influence the abundance of tryptic peptides. However, the Apo strain showed increased coproporphyrinogen III oxidase and ferrochelatase levels. A putative ferrous iron transporter, homologous to LIT1 and TcIT from Leishmania major and Trypanosoma cruzi, was identified for the first time. Label-free parallel reaction monitoring targeted mass spectrometry also showed that S. culicis Iron Transporter (ScIT) increased 1.6- and 16.4-fold in WTR and Apo strains compared to WT. Accordingly, antibody-mediated blockage of ScIT decreased by 28.0% and 40.0% intracellular Fe2+concentration in both WTR and Apo strains, whereas no effect was detected in WT. In a heme-depleted medium, adding 10 µM hemin decreased ScIT transcript levels in Apo, whereas 10 µM PPIX, the substrate of ferrochelatase, increased intracellular Fe2+ concentration and ferric iron reduction. Overall, the data suggest mechanisms dependent on de novo heme synthesis (and its substrates) in the Apo strain to overcome reduced heme availability. Given the importance of heme and Fe2+ as cofactors in metabolic pathways, including oxidative phosphorylation and antioxidant systems, this study provides novel mechanistic insights associated with H2O2 resistance in S. culicis.

Advances on the Experimental Research in Resistant Hypertension.

PURPOSE OF REVIEW: Resistant Hypertension (RH) poses a significant public health challenge, contributing to increased mortality, cardiovascular events and organ damage. Both clinical and experimental research are striving for higher standards in a translational manner to integrate new findings and confirm hypotheses. Considering that many are the aspects of RH that are still under investigation, this review aims to shed light on the advances made in experimental research concerning RH. It seeks to underscore the pivotal role of experimental studies in shaping clinical practices and also explore future perspectives. RECENT FINDINGS: It is important to emphasize the significance of experimental models, primarily for advancing our understanding: experimental models have greatly contributed to our comprehension of the underlying mechanisms in RH, including factors like sympathetic activation, endothelial dysfunction and structural vessel abnormalities. Secondly, for assessing treatment approaches: animal models have also played a crucial role in evaluating the potential effectiveness of diverse treatment approaches for RH. These encompass both pharmacological options, involving combinations of established drugs or novel pharmaceuticals, and non-pharmacological alternatives, which include surgical procedures like renal denervation, medical devices like baroreceptor stimulators, and lifestyle modifications. The most lacking component in translational research is the fact that there is no well-established animal model that perfectly replicates RH. Consequently, alternative strategies, including the combination of models, must be considered. What remains clear is that the development of animal models closely mimicking RH holds the promise of providing valuable insights into the essential mechanisms and responses necessary to combat or slow the global progression of RH.

Genomic surveillance of malaria parasites in an indigenous community in the Peruvian Amazon.

Hard-to-reach communities represent Peru's main challenge for malaria elimination, but information about transmission in these areas is scarce. Here, we assessed Plasmodium vivax (Pv) and P. falciparum (Pf) transmission dynamics, resistance markers, and Pf hrp2/3 deletions in Nueva Jerusalén (NJ), a remote, indigenous community in the Peruvian Amazon with high population mobility. We collected samples from November 2019 to May 2020 by active (ACD) and passive case detection (PCD) in NJ. Parasites were identified with microscopy and PCR. Then, we analyzed a representative set of positive-PCR samples (Pv = 68, Pf = 58) using highly-multiplexed deep sequencing assays (AmpliSeq) and compared NJ parasites with ones from other remote Peruvian areas using population genetics indexes. The ACD intervention did not reduce malaria cases in the short term, and persistent malaria transmission was observed (at least one Pv infection was detected in 96% of the study days). In Nueva Jerusalen, the Pv population had modest genetic diversity (He = 0.27). Pf population had lower diversity (He = 0.08) and presented temporal clustering, one of these clusters linked to an outbreak in February 2020. Moreover, Pv and Pf parasites from NJ exhibited variable levels of differentiation (Pv Fst = 0.07-0.52 and Pf Fst = 0.11-0.58) with parasites from other remote areas. No artemisin resistance mutations but chloroquine (57%) and sulfadoxine-pyrimethamine (35-67%) were detected in NJ's Pf parasites. Moreover, pfhrp2/3 gene deletions were common (32-50% of parasites with one or both genes deleted). The persistent Pv transmission and the detection of a Pf outbreak with parasites genetically distinct from the local ones highlight the need for tailored interventions focusing on mobility patterns and imported infections in remote areas to eliminate malaria in the Peruvian Amazon.

Plasmodium vivax genomic surveillance in the Peruvian Amazon with Pv AmpliSeq assay.

BACKGROUND: Plasmodium vivax is the most predominant malaria species in Latin America, constituting 71.5% of malaria cases in 2021. With several countries aiming for malaria elimination, it is crucial to prioritize effectiveness of national control programs by optimizing the utilization of available resources and strategically implementing necessary changes. To support this, there is a need for innovative approaches such as genomic surveillance tools that can investigate changes in transmission intensity, imported cases and sources of reintroduction, and can detect molecular markers associated with drug resistance. METHODOLOGY/PRINCIPAL FINDINGS: Here, we apply a modified highly-multiplexed deep sequencing assay: Pv AmpliSeq v2 Peru. The tool targets a newly developed 41-SNP Peru barcode for parasite population analysis within Peru, the 33-SNP vivaxGEN-geo panel for country-level classification, and 11 putative drug resistance genes. It was applied to 230 samples from the Peruvian Amazon (2007-2020), generating baseline surveillance data. We observed a heterogenous P. vivax population with high diversity and gene flow in peri-urban areas of Maynas province (Loreto region) with a temporal drift using all SNPs detected by the assay (nSNP = 2909). In comparison, in an indigenous isolated area, the parasite population was genetically differentiated (FST = 0.07-0.09) with moderate diversity and high relatedness between isolates in the community. In a remote border community, a clonal P. vivax cluster was identified, with distinct haplotypes in drug resistant genes and ama1, more similar to Brazilian isolates, likely representing an introduction of P. vivax from Brazil at that time. To test its applicability for Latin America, we evaluated the SNP Peru barcode in P. vivax genomes from the region and demonstrated the capacity to capture local population clustering at within-country level. CONCLUSIONS/SIGNIFICANCE: Together this data shows that P. vivax transmission is heterogeneous in different settings within the Peruvian Amazon. Genetic analysis is a key component for regional malaria control, offering valuable insights that should be incorporated into routine surveillance.

Comparison of P-glycoprotein gene expression of two Haemonchus contortus isolates from Yucatan, Mexico, with resistant or susceptible phenotype to ivermectin in relation to a susceptible reference strain.

The variability in the expression of different P-glycoprotein (P-gp) genes in parasitic nematodes of ruminants such as Haemonchus contortus (Hco-pgp) may be caused by different factors including nematode biology, geographical region and anthelmintic pressure. This study analysed the relative expression level of 10 P-gp genes in two H. contortus (Hco-pgp) field isolates from Yucatan, Mexico: 1) PARAISO (IVM-resistant) and 2) FMVZ-UADY (IVM-susceptible). These isolates were compared with a susceptible reference isolate from Puebla, Mexico, namely "CENID-SAI". In all cases H. contortus adult males were used. The Hco-pgp genes (1, 2, 3, 4, 9, 10, 11, 12, 14 and 16) were analysed for each isolate using the RT-qPCR technique. The Hco-pgp expressions were pairwise compared using the 2-ΔΔCt method and a t-test. The PARAISO isolate showed upregulation compared to the CENID-SAI isolate for Hco-pgp 1, 3, 9, 10 and 16 (P < 0.05), and the PARAISO isolate showed upregulation vs. FMVZ-UADY isolate for Hco-pgp 2 and 9 (P < 0.05), displaying 6.58- and 5.93-fold differences (P < 0.05), respectively. In contrast, similar Hco-pgp gene expression levels were recorded for FMVZ-UADY and CENID-SAI isolates except for Hco-pgp1 (P <0.1), which presented a significant upregulation (6.08-fold). The relative expression of Hco-pgp allowed confirming the IVM-resistant status of the PARAISO isolate and the IVM-susceptible status of the FMVZ-UADY isolate when compared to the CENID-SAI reference isolate. Therefore, understanding the association between the Hco-pgp genes expression of H. contortus and its IVM resistance status could help identifying the genes that could be used as molecular markers in the diagnosis of IVM resistance. However, it is important to consider the geographic origin of the nematode isolate and the deworming history at the farm of origin.

Brazil's battle against Rhipicephalus (Boophilus) microplus ticks: current strategies and future directions.

Ticks are parasitic arthropods that cause significant economic losses to livestock production worldwide. Although Rhipicephalus (Boophilus) microplus, the cattle tick, occurs throughout the Brazilian territory, there is no official program to control this tick, which is the vector of tick fever pathogens. We address the situation of R. (B.) microplus resistance to synthetic acaricides in Brazil, including cattle tick management; the status of tick resistance per Brazilian state; the history of resistance occurrence of different acaricides; multiple resistance occurrence; and the main strategies for integrated tick management. Tick control in Brazil is characterized by management errors. Local laboratories affiliated with federal and state research institutions and universities employ the Adult Immersion Test as a primary diagnostic method to assess acaricide resistance to topically applied drugs. Only three states (Acre, Amapá, and Amazonas) have no reports on resistant populations. Misinformation on tick control strategies, misuse of available products for tick control, no adoption of Integrated Parasite Management (IPM) practices, low technical support to producers, and the high-speed emergence of acaricide-resistant tick populations are the main problems. We also propose a list of needs and priorities for cattle tick control regarding communication, research, and policies.

Molecular Surveillance of Artemisinin-Resistant Plasmodium falciparum Parasites in Mining Areas of the Roraima Indigenous Territory in Brazil.

Multidrug- and artemisinin-resistant (ART-R) Plasmodium falciparum (Pf) parasites represent a challenge for malaria elimination worldwide. Molecular monitoring in the Kelch domain region (pfk13) gene allows tracking mutations in parasite resistance to artemisinin. The increase in illegal miners in the Roraima Yanomami indigenous land (YIL) could favor ART-R parasites. Thus, this study aimed to investigate ART-R in patients from illegal gold mining areas in the YIL of Roraima, Brazil. A questionnaire was conducted, and blood was collected from 48 patients diagnosed with P. falciparum or mixed malaria (Pf + P. vivax). The DNA was extracted and the pfk13 gene was amplified by PCR. The amplicons were subjected to DNA-Sanger-sequencing and the entire amplified fragment was analyzed. Among the patients, 96% (46) were from illegal mining areas of the YIL. All parasite samples carried the wild-type genotypes/ART-sensitive phenotypes. These data reinforce the continued use of artemisinin-based combination therapies (ACTs) in Roraima, as well as the maintenance of systematic monitoring for early detection of parasite populations resistant to ART, mainly in regions with an intense flow of individuals from mining areas, such as the YIL. This is especially true when the achievement of falciparum malaria elimination in Brazil is planned and expected by 2030.

Characterization of antimalarial activity of artemisinin-based hybrid drugs.

In response to the spread of artemisinin (ART) resistance, ART-based hybrid drugs were developed, and their activity profile was characterized against drug-sensitive and drug-resistant Plasmodium falciparum parasites. Two hybrids were found to display parasite growth reduction, stage-specificity, speed of activity, additivity of activity in drug combinations, and stability in hepatic microsomes of similar levels to those displayed by dihydroartemisinin (DHA). Conversely, the rate of chemical homolysis of the peroxide bonds is slower in hybrids than in DHA. From a mechanistic perspective, heme plays a central role in the chemical homolysis of peroxide, inhibiting heme detoxification and disrupting parasite heme redox homeostasis. The hybrid exhibiting slow homolysis of peroxide bonds was more potent in reducing the viability of ART-resistant parasites in a ring-stage survival assay than the hybrid exhibiting fast homolysis. However, both hybrids showed limited activity against ART-induced quiescent parasites in the quiescent-stage survival assay. Our findings are consistent with previous results showing that slow homolysis of peroxide-containing drugs may retain activity against proliferating ART-resistant parasites. However, our data suggest that this property does not overcome the limited activity of peroxides in killing non-proliferating parasites in a quiescent state.

Photodynamic therapy offers a novel approach to managing miltefosine-resistant cutaneous leishmaniasis.

Cutaneous leishmaniasis (CL) is a neglected disease caused by Leishmania parasites. The oral drug miltefosine is effective, but there is a growing problem of drug resistance, which has led to increasing treatment failure rates and relapse of infections. Photodynamic therapy (PDT) combines a light source and a photoactive drug to promote cell death by oxidative stress. Although PDT is effective against several pathogens, its use against drug-resistant Leishmania parasites remains unexplored. Herein, we investigated the potential of organic light-emitting diodes (OLEDs) as wearable light sources, which would enable at-home use or ambulatory treatment of CL. We also assessed its impact on combating miltefosine resistance in Leishmania amazonensis-induced CL in mice. The in vitro activity of OLEDs combined with 1,9-dimethyl-methylene blue (DMMB) (OLED-PDT) was evaluated against wild-type and miltefosine-resistant L. amazonensis strains in promastigote (EC50 = 0.034 µM for both strains) and amastigote forms (EC50 = 0.052 µM and 0.077 µM, respectively). Cytotoxicity in macrophages and fibroblasts was also evaluated. In vivo, we investigated the potential of OLED-PDT in combination with miltefosine using different protocols. Our results demonstrate that OLED-PDT is effective in killing both strains of L. amazonensis by increasing reactive oxygen species and stimulating nitric oxide production. Moreover, OLED-PDT showed great antileishmanial activity in vivo, allowing the reduction of miltefosine dose by half in infected mice using a light dose of 7.8 J/cm2 and 15 µM DMMB concentration. In conclusion, OLED-PDT emerges as a new avenue for at-home care and allows a combination therapy to overcome drug resistance in cutaneous leishmaniasis.

Efficacy and Safety of Radiofrequency-Based Renal Denervation on Resistant Hypertensive Patients: A Systematic Review and Meta-analysis.

INTRODUCTION: New therapies for resistant hypertension (RH), including renal denervation (RDN), have been studied. AIM: Access the safety and effectiveness of radiofrequency-based RDN vs pharmacological treatment for RH. METHODS: A thorough literature search was conducted across PubMed, EMBASE, and the Cochrane databases, focusing on studies that compared the effects of radiofrequency-based RDN versus pharmacological treatment for RH. Treatment effects for binary and continuous endpoints were pooled and used, respectively, odds-ratio (OR) and mean differences (MD) with 95% confidence intervals (CI) to analyze continuous outcomes. RESULTS: In the 10 included studies, involving 1.182 patients, 682 received radiofrequency-based RDN. The follow-up period ranged from 6 to 84 months. Analysis revealed that the RDN group had a significant reduction in office systolic blood pressure (BP) (MD - 9.5 mmHg; 95% CI - 16.81 to - 2.29; P = 0.01), office diastolic BP (MD - 5.1 mmHg; 95% CI - 8.42 to - 2.80; P < 0.001), 24 h systolic BP (MD - 4.8 mmHg; 95% CI - 7.26 to - 2.42; P < 0.001). For 24 h diastolic BP RDN did not have a significant reduction (MD - 2.3 mmHg; 95% CI - 4.19 to - 0.52; P = 0.012). The heterogeneity between the studies was high, visible in the funnel and Baujat plots. The OR was non-significant for non-serious adverse events, but also clinically significant for hypertensive crises and strokes for the RDN group. CONCLUSIONS: While the pharmacological regimen of 3 or more anti-hypertensive, including a diuretic, still be the first-line option for RH treatment, our results support that radiofrequency-based RDN is superior in reducing global BP and is safe.

Temporal and spatial dynamics of Plasmodium falciparum clonal lineages in Guyana.

Plasmodium parasites, the causal agents of malaria, are eukaryotic organisms that obligately undergo sexual recombination within mosquitoes. In low transmission settings, parasites recombine with themselves, and the clonal lineage is propagated rather than broken up by outcrossing. We investigated whether stochastic/neutral factors drive the persistence and abundance of Plasmodium falciparum clonal lineages in Guyana, a country with relatively low malaria transmission, but the only setting in the Americas in which an important artemisinin resistance mutation (pfk13 C580Y) has been observed. We performed whole genome sequencing on 1,727 Plasmodium falciparum samples collected from infected patients across a five-year period (2016-2021). We characterized the relatedness between each pair of monoclonal infections (n = 1,409) through estimation of identity-by-descent (IBD) and also typed each sample for known or candidate drug resistance mutations. A total of 160 multi-isolate clones (mean IBD ≥ 0.90) were circulating in Guyana during the study period, comprising 13 highly related clusters (mean IBD ≥ 0.40). In the five-year study period, we observed a decrease in frequency of a mutation associated with artemisinin partner drug (piperaquine) resistance (pfcrt C350R) and limited co-occurence of pfcrt C350R with duplications of plasmepsin 2/3, an epistatic interaction associated with piperaquine resistance. We additionally observed 61 nonsynonymous substitutions that increased markedly in frequency over the study period as well as a novel pfk13 mutation (G718S). However, P. falciparum clonal dynamics in Guyana appear to be largely driven by stochastic factors, in contrast to other geographic regions, given that clones carrying drug resistance polymorphisms do not demonstrate enhanced persistence or higher abundance than clones carrying polymorphisms of comparable frequency that are unrelated to resistance. The use of multiple artemisinin combination therapies in Guyana may have contributed to the disappearance of the pfk13 C580Y mutation.

First report of ivermectin resistance in cyathostomins (small strongyles) of horses in Argentina.

In Argentina, as in the rest of the world, cyathostomins are the most common nematodes parasitizing horses. Control is based almost exclusively on the administration of benzimidazoles, pyrimidines, and macrocyclic lactones. However, intensive use of these drugs is resulting in the development of anthelmintic resistance (AR). For example, AR to benzimidazoles is currently distributed throughout Argentina, while incipient AR to pyrimidines (pyrantel embonate) is appearing in areas where this drug is used. Macrocyclic lactones and especially ivermectin, are by far the most used drugs by the vast majority of equine premises in the country. Although ivermectin has been used since 1982, its efficacy against equine strongylid parasites has remained very high until the present. In this study we report for the first time, the presence of a cyathostomin population with resistance to ivermectin in adult horses belonging to an equine premise located in central Argentina. Fecal egg count reduction tests (FECRT) were performed following the most recent guidelines of the World Association for the Advancement of Veterinary Parasitology (WAAVP) for the diagnosis of anthelmintic resistance (research protocol) and resistance was considered when the Upper 90% Credible Interval fell below the expected efficacy threshold of 99.9%. Calculations were carried out using two different online calculation interfaces suggested by WAAVP. For the 14-day post-treatment interval, ivermectin efficacy was 79.5% (90% Credible Interval: 68.1-88.8) and 79.3% (74.2-83.6.3%) with the two methods, respectively. At 19 days post treatment, fecal egg count reductions were 68.6% (50.5-83.1) and 68.4% (61.9-74.1), respectively. At both intervals, this cyathostomin population fullfilled the criteria for AR. These findings suggest dispersion of ivermectin resistant cyathostomins in Argentina. Given the widespread use of macrocyclic lactones, it is important that veterinarians and the equine industry promote a more selective and evidence-based use of these drugs and establish routine monitoring to determine anthelmintic field efficacy to detect treatment failures as early as possible and avoid potential health problems as well as further spread of resistant genes.