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Chitinases, a group of glycosyl hydrolases (GHs), catalyze the degradation of chitin by releasing N-acetylglucosamine subunits. GHs can be found in all three domains of life. Among the three GH families (GH18, GH19, and GH20), GH18 chitinases are the most conserved and extensively studied. These enzymes have been implicated in nutrition, immune modulation, invasion, and virulence across diverse pathogens. In some parasitic protists, GH18 chitinases are essential for transmission. However, in kinetoplastids, including Leishmania spp., these enzymes remain poorly characterized. This study aimed to identify and characterize chitinase across kinetoplastids, with a particular focus on GH18 chitinase in Leishmania braziliensis , the causative agent of muco-cutaneous leishmaniasis. A bioinformatic pipeline was implemented to retrieve and annotate chitinase genes from multiple databases. Catalytic domains and subcellular localization were identified using dedicated computational tools. Phylogenetic relationships were reconstructed in MEGA12 using maximum likelihood and neighbor-joining methods. RNA-seq data were analyzed to evaluate stage-specific expression. Structural models of L. braziliensis GH18 chitinase (Lbr_ChGH18) were created with AlphaFold and subsequently refined. We identified GH18 chitinases genes across Leishmania species and other kinetoplastids, together with GH19 and GH20 chitinase genes. Lbr_ChGH18 was detected across all life-cycle stages, with peak levels in amastigotes. Docking analyses identified closantel, argifin, and argadin as potential inhibitors of Lbr_ChGH18. Epitope prediction revealed conserved B- and T-cell epitopes in GH18 chitinases from Old and New World Leishmania , capable of binding multiple HLA class I and II molecules, highlighting their potential as diagnostic and vaccine candidates. The discovery of GH20 chitinase-like genes in Trypanosoma species offers new insights into the evolution and functional diversification of GHs in kinetoplastids. The high conservation and expression of GH18 chitinases underscore their potential as promising targets for drug and vaccine development against leishmaniasis.

One peculiarity of protists belonging to classes Kinetoplastea and Diplonemea within the phylum Euglenozoa is compartmentalisation of most glycolytic enzymes within peroxisomes that are hence called glycosomes. This pathway is not sequestered in peroxisomes of the third Euglenozoan class, Euglenida. Previous analysis of well-studied kinetoplastids, the ‘TriTryps’ parasites Trypanosoma brucei , Trypanosoma cruzi and Leishmania spp., identified within glycosomes other metabolic processes usually not present in peroxisomes. In addition, trypanosomatid peroxins, i.e. proteins involved in biogenesis of these organelles, are divergent from human and yeast orthologues. In recent years, genomes, transcriptomes and proteomes for a variety of euglenozoans have become available. Here, we track the possible evolution of glycosomes by querying these databases, as well as the genome of Naegleria gruberi , a non-euglenozoan, which belongs to the same protist supergroup Discoba. We searched for orthologues of TriTryps proteins involved in glycosomal metabolism and biogenesis. Predicted cellular location(s) of each metabolic enzyme identified was inferred from presence or absence of peroxisomal-targeting signals. Combined with a survey of relevant literature, we refine extensively our previously postulated hypothesis about glycosome evolution. The data agree glycolysis was compartmentalised in a common ancestor of the kinetoplastids and diplonemids, yet additionally indicates most other processes found in glycosomes of extant trypanosomatids, but not in peroxisomes of other eukaryotes were either sequestered in this ancestor or shortly after separation of the two lineages. In contrast, peroxin divergence is evident in all euglenozoans. Following their gain of pathway complexity, subsequent evolution of peroxisome/glycosome function is complex. We hypothesize compartmentalisation in glycosomes of glycolytic enzymes, their cofactors and subsequently other metabolic enzymes provided selective advantage to kinetoplastids and diplonemids during their evolution in changing marine environments. We contend two specific properties derived from the ancestral peroxisomes were key: existence of nonselective pores for small solutes and the possibility of high turnover by pexophagy. Critically, such pores and pexophagy are characterised in extant trypanosomatids. Increasing amenability of free-living kinetoplastids and recently isolated diplonemids to experimental study means our hypothesis and interpretation of bioinformatic data are suited to experimental interrogation.

Hexokinase from Leishmania mexicana was purified to homogeneity from a glycosome-enriched fraction obtained after a differential centrifugation of promastigote form. The kinetic properties of the pure enzyme were determined and the Km values for glucose (Km = 66 μM) and ATP (Km = 303 μM) were comparable to those from hexokinase of Trypanosoma cruzi. L. mexicana hexokinase was able to use fructose (Km = 142 μM), which reflects the condition found in the insect host. In contrast with hexokinases from other trypanosomatids, the enzyme exhibited a moderate sensitivity to inhibition by glucose 6-phosphate. This inhibition was competitive with respect to both ATP and glucose, indicating that an allosteric site for glucose 6-phosphate does not exist in this enzyme. The enzyme was also inhibited by inorganic pyrophosphate, the inhibition being higher than that observed for T. cruzi enzyme. As expected, the enzyme was localized, by immunofluorescence analysis, in glycosomes and is present in both promastigotes and true amastigotes obtained from hamster lesion. Hexokinase specific activity increased with the aging of promastigote culture, and this increment was related to glucose consumption. However, the level of the hexokinase protein remains constant as determined by Western blotting. Several hypotheses are discussed to explain this result.

Trypanosomatids have the unique feature of compartmentalizing the major part of the glycolytic pathway inside peroxisome‐related organelles called glycosomes. However, these organelles also contain enzymes of several other important pathways involved in both catabolic and anabolic processes. The enzyme content and the metabolic role of glycosomes differ between trypanosomatid species and between their life cycle stages. Several of the glycosomal pathways have been shown to be important for the viability, pathogenicity, and/or virulence of different trypanosomatid parasites. Additionally, the correct compartmentalization of glycosomal enzymes inside the organelles appeared to be vital for these pathogens. Therefore, many of these enzymes, as well as the proteins involved in the translocation of metabolites across the glycosomal membrane and peroxins (PEXs), proteins responsible for the biogenesis of glycosomes, are candidate drug targets. Glycosomal enzymes and PEX proteins of Trypanosoma brucei, T. cruzi, and Leishmania spp. are being studied, and compounds that interfere with their functioning are being developed for use as lead drugs against the diseases caused by these parasites. Potent, selective inhibitors of several enzymes have been obtained that exert trypanocidal activity on parasites cultured in vitro and have no or only little effect on growth of human cells. In addition, some compounds showed anti‐parasite activity in experimentally infected animals.

The increasing burden of cancer represents a substantial problem for Latin America and the Caribbean. Two Lancet Oncology Commissions in 2013 and 2015 highlighted potential interventions that could advance cancer care in the region by overcoming existing challenges. Areas requiring improvement included insufficient investment in cancer control, non-universal health coverage, fragmented health systems, inequitable concentration of cancer services, inadequate registries, delays in diagnosis or treatment initiation, and insufficient palliative services. Progress has been made in key areas but remains uneven across the region. An unforeseen challenge, the COVID-19 pandemic, strained all resources, and its negative effect on cancer control is expected to continue for years. In this Series paper, we summarise progress in several aspects of cancer control since 2015, and identify persistent barriers requiring commitment of additional resources to reduce the cancer burden in Latin America and the Caribbean.

Species recognition in lichen-forming fungi has been a challenge because of unsettled species concepts, few taxonomically relevant traits, and limitations of traditionally used morphological and chemical characters for identifying closely related species. Here we analyze species diversity in the cosmopolitan genus Protoparmelia s.l. The ~25 described species in this group occur across diverse habitats from the boreal-arctic/alpine to the tropics, but their relationship to each other remains unexplored. In this study, we inferred the phylogeny of 18 species currently assigned to this genus based on 160 specimens and six markers: mtSSU, nuLSU, ITS, RPB1, MCM7, and TSR1. We assessed the circumscription of species-level lineages in Protoparmelia s. str. using two coalescent-based species delimitation methods--BP&P and spedeSTEM. Our results suggest the presence of a tropical and an extra-tropical lineage, and eleven previously unrecognized distinct species-level lineages in Protoparmelia s. str. Several cryptic lineages were discovered as compared to phenotype-based species delimitation. Many of the putative species are supported by geographic evidence.

Congenital hyperinsulinism (CHI) is a heterogeneous disorder of insulin dysregulation, leading to hypoglycemia. This study describes the clinical characteristics, genetics, and management of CHI in Argentina. We retrospectively reviewed 70 probands diagnosed with CHI (2008-2021) at multiple centres across Argentina. Clinical, biochemical, imaging, and treatment data were analyzed. Genetic testing was performed in 49 probands using Sanger and targeted next-generation sequencing of CHI-related genes. Transient CHI was identified in 23/70 (33%) probands, with a median duration of 2 months. Risk factors for perinatal stress-induced hyperinsulinism (PSHI) were present in 85% of transient cases. Persistent CHI was diagnosed in 44/70 (63%) individuals, of whom 31 responded to diazoxide. Late-onset CHI (diagnosed >3 years) was identified in 3 children. A pathogenic variant was detected in 19/49 (39%) probands, all had persistent CHI. ABCC8 variants were most common accounting for 68% (13/19) of diagnoses. Imaging in 17 cases revealed focal disease in 8, diffuse disease in 8, and atypical disease in 1 individual. Seven individuals with focal disease underwent lesionectomy, which was curative in 5 (71%). Three children with diffuse disease required near-total pancreatectomy, with one developing postoperative diabetes. This study provides the largest CHI cohort reported from South America and highlights the clinical and genetic heterogeneity of the condition. Transient CHI was often associated with PSHI risk factors, while persistent CHI was predominantly linked to K-ATP channel variants. The findings underscore the importance of genetics and imaging for CHI management and emphasize the need for increased access to molecular diagnostics.

Despite men-who-have-sex-with-men (MSM) from Latin America (LA) are still a vulnerable population for known health-related conditions and social problems, availability of comparable data across LA countries for assessment and monitoring purposes is limited. The objective of this article is to present the study design and the questionnaire of LAMIS-2018 (Latin America MSM Internet Survey), its recruitment strategy, rates and sources by country, and the lessons learned from its implementation. LAMIS-2018 was a cross-sectional, internet-based survey targeting MSM living in 18 LA countries (Argentina, Bolivia, Brazil, Chile, Colombia, Costa Rica, Ecuador, El Salvador, Guatemala, Honduras, Mexico, Nicaragua, Panama, Paraguay, Peru, Suriname, Uruguay, and Venezuela) that gathered data about sexual behaviors, HIV/STI and viral hepatitis knowledge, prophylactic use of antiretrovirals, psychosocial health, and access to sexual health services. The survey went online for four months and was available in three languages (Spanish, Portuguese, and Dutch). Promotion was carried out using dating apps, websites, social networks, and by community-based and academic organizations of each participating country directly in gay venues and in their own premises. Overall, 64,655 MSM participated in LAMIS-2018. Dating apps and websites were the most important recruitment source in most countries, except for Honduras, Nicaragua, and Suriname, where community-based organizations recruited most of the participants. Beyond the LAMIS-2018 implementation description, we highlight the feasibility of such a study in this context, based on the collaboration between community-based and academic organizations to obtain a large sample of MSM in the region. LAMIS-2018 data will contribute to identify determinants of risk behaviors and prevention needs of vulnerable MSM populations in each country of the region.

Hemophilia is an X-linked inherited bleeding disorder, classified as type A or type B. Therapeutic advances offer new treatment options that improve disease control and reduce associated complications, including inhibitor development and hemophilic arthropathy. This document aims to update the Mexican hemophilia consensus, reviewing current evidence on diagnosis and management, and addressing gaps in the treatment and follow-up of patients in Mexico, aligning local needs with international recommendations. A PubMed literature search covering the last five years (up to September 2025) was conducted, prioritizing consensus statements, guidelines, and systematic reviews. Using the Delphi methodology, a structured questionnaire was submitted electronically to forty-four experts. Aspects without initial agreement were discussed at an in-person meeting. Consensus was defined as at least 80% of votes in favor. Recommendations were issued across six domains: laboratory diagnosis, genetic testing, management of hemophilia A and B without and with inhibitors, adjuvant treatments, and gene therapy. The recommendations address prophylaxis with coagulation factor concentrates, non-factor therapies, immune tolerance induction, perioperative management, pain management, and eligibility criteria and follow-up protocols for gene therapy with adeno-associated viral vectors. This consensus provides updated, evidence-based recommendations adapted to the Mexican healthcare context, identifying priority areas, including timely access to non-factor therapies and gene therapy, development of a national referral network for complex cases, and inclusion of novel therapeutic agents in the institutional essential medicines list, with the aim of improving the quality of life of people with hemophilia in Mexico.

Antiretroviral therapy has changed the natural history of human immunodeficiency virus (HIV) infection in developed countries, where it has become a chronic disease. This clinical scenario requires a new approach to simplify follow-up appointments and facilitate access to healthcare professionals. We developed a new internet-based home care model covering the entire management of chronic HIV-infected patients. This was called Virtual Hospital. We report the results of a prospective randomised study performed over two years, comparing standard care received by HIV-infected patients with Virtual Hospital care. HIV-infected patients with access to a computer and broadband were randomised to be monitored either through Virtual Hospital (Arm I) or through standard care at the day hospital (Arm II). After one year of follow up, patients switched their care to the other arm. Virtual Hospital offered four main services: Virtual Consultations, Telepharmacy, Virtual Library and Virtual Community. A technical and clinical evaluation of Virtual Hospital was carried out. Of the 83 randomised patients, 42 were monitored during the first year through Virtual Hospital (Arm I) and 41 through standard care (Arm II). Baseline characteristics of patients were similar in the two arms. The level of technical satisfaction with the virtual system was high: 85% of patients considered that Virtual Hospital improved their access to clinical data and they felt comfortable with the videoconference system. Neither clinical parameters [level of CD4+ T lymphocytes, proportion of patients with an undetectable level of viral load (p = 0.21) and compliance levels >90% (p = 0.58)] nor the evaluation of quality of life or psychological questionnaires changed significantly between the two types of care. Virtual Hospital is a feasible and safe tool for the multidisciplinary home care of chronic HIV patients. Telemedicine should be considered as an appropriate support service for the management of chronic HIV infection. Clinical-Trials.gov: NCT01117675.