👤 Agustín Izquierdo

Increased fasting and postprandial triglyceride levels are risk factors for cardiovascular disease (CVD). Partially metabolized triglyceride-rich lipoproteins (TRLs) termed remnants are created when intestinally-derived chylomicrons and liver secreted very low density lipoproteins (VLDLs) interact with lipoprotein lipase (LpL) situated on the luminal surface of capillary endothelial cells. Higher circulating remnant levels have been implicated as the reason for the relationship between TRL levels and CVD. We hypothesized that nascent lipoproteins not only remnants are atherogenic. To test this, we created mice with induced whole-body lipoprotein lipase (LpL) deficiency combined with LDL receptor (LDLR) deficiency. On an atherogenic Western-type diet (WD), male and female mice with induced global LpL deficiency (iLpl Show less

Which phenotypes can be confidently linked to a genetic etiology in males with congenital hypogonadotropic hypogonadism (CHH) resulting in absent or arrested puberty? In this systematic review and reclassification of the disease-causing potential of gene variants using the recommendations of the American College of Medical Genetics and Genomics (ACMG) and the Association for Molecular Pathology (AMP), we found that absent or arrested puberty in males with CHH was linked to 93 genes, of which 29 were unequivocally disease-causing. The number of genes and phenotype characterizations associated with CHH in males has rapidly increased since the advent of next-generation sequencing technologies; however, the quality of the evidence for the interpretation of the causal relationship of gene variants is limited due to the lack of systematic criteria applied to the assessment of the pathogenic potential of the variants. We performed a systematic review of original articles indexed in PubMed until 5 October 2022 and using the search terms '(('hypogonadotropic hypogonadism' OR Kallmann) AND (sequencing OR mutation OR variant))' limited to 'Humans' and 'English'. After two investigators undertook the literature search independently, titles and abstracts of all records were reviewed by four of the authors to identify those articles to be included in the full-text review. Clinical data and the association with gene variants were extracted from males with delayed or arrested puberty due to CHH according to the article authors' criteria. Raw sequence variant information was used to reevaluate their pathogenic potential applying the ACMG/AMP guidelines for variant classification with InterVar. Subsequently, we considered the phenotype specificity criteria for sequence variant pathogenicity classification, based on curated genes associated with CHH, and classified patients into three categories: with monogenic disease-causing variants in genes associated with CHH, with variants in genes whose causality is unclear, and with variants that are not disease-causing. From a total of 1083 records, we included 245 publications with 775 male patients with CHH resulting in absent or arrested puberty, carrying 1001 variants in 93 genes. Gene variants were detected by Sanger sequencing in 61.8% of the cases and by next-generation sequencing (NGS) technologies in the rest. After variant reclassification of causality, 278 individuals were not considered to have a bona fide disease-causing gene variant, and 497 patients were reclassified as carrying at least one disease-causing variant associated with CHH. They carried 503 different disease-causing variants in 29 genes. Spontaneous puberty was absent in 85.5% and arrested in 14.5% of the 497 individuals with CHH carrying bona fide disease-causing variants. In males with absent puberty (complete hypogonadotrophic hypogonadism), FGFR1 and ANOS1 were the most frequently affected genes, accounting for 53.5% of the disease-causing variants. In males with incomplete spontaneous puberty (partial hypogonadotrophic hypogonadism), variants in FGFR1, NR0B1, and GNRHR were found in 70.3% of the cases. Micropenis, cryptorchidism and/or low testicular volume, considered 'red flags' for the diagnosis of CHH, were found in less than 30% of males, with cryptorchidism being more frequently observed in association with variants in FGFR1, ANOS1, KISS1R, SOX10, and GNRH1, and micropenis being more prevalent in patients with variants in TACR3, KISS1R, or GNRH1. Clinical manifestations in non-reproductive organs were found in 39.8% of the patients with bona fide disease-causing variants. Because we included studies going back to the initial genetic reports of patients with CHH, results obtained by Sanger sequencing represent a significant proportion of the whole sample, which may be biased by the use of a candidate gene strategy. A subanalysis of cases studied by NGS modified the results only slightly. This comprehensive synthesis will help clinicians in the guidance of reverse phenotyping once the precise genetic diagnosis is established, and researchers in the design of functional studies to clarify the role of specific sequence variants in the etiology of male CHH. A genetic etiology of CHH in males with absent or arrested puberty should be considered even in the absence of micropenis, cryptorchidism, and/or low testicular volume. This work was partially funded by grants PICT I-A-2018-02972 of Fondo de Promoción Científica y Técnica (FONCYT), PICT A-CAT III2021-73 of Fondo Argentino Sectorial (FONARSEC) and Proyectos de Redes Federales de Alto Impacto 2023 #3 of Ministerio de Ciencia, Tecnología e Innovación, Argentina. Competing interests: None declared. None declared. Show less

The effect of increased triglycerides (TGs) as an independent factor in atherosclerosis development has been contentious, in part, because severe hypertriglyceridemia associates with low levels of low-density lipoprotein cholesterol (LDL-C). To test whether hyperchylomicronemia, in the absence of markedly reduced LDL-C levels, contributes to atherosclerosis, we created mice with induced whole-body lipoprotein lipase (LpL) deficiency combined with LDL receptor (LDLR) deficiency. On an atherogenic Western-type diet (WD), male and female mice with induced global LpL deficiency (i Show less

To investigate whether an exercise intervention using the VIVIFRAIL© protocol has benefits for inflammatory and functional parameters in different frailty status. This is a randomized clinical trial in an outpatient geriatrics clinic including older adults ≥60 years. For each frailty state (frail, pre-frail and robust), forty-four volunteers will be randomly allocated to the control group (n = 22) and the intervention group (n = 22) for 12 weeks. In the control group, participants will have meetings of health education while those in the intervention group will be part of a multicomponent exercise program (VIVIFRAIL©) performed five times a week (two times supervised and 3 times of home-based exercises). The primary outcome is a change in the inflammatory profile (a reduction in inflammatory interleukins [IL-6, TNF- α, IL1beta, IL-17, IL-22, CXCL-8, and IL-27] or an increase in anti-inflammatory mediators [IL-10, IL1RA, IL-4]). Secondary outcomes are change in physical performance using the Short Physical Performance Battery, handgrip strength, fatigue, gait speed, dual-task gait speed, depressive symptoms, FRAIL-BR and SARC-F scores, and quality of life at the 12-week period of intervention and after 3 months of follow-up. We expect a reduction in inflammatory interleukins or an increase in anti-inflammatory mediators in those who performed the VIVIFRAIL© protocol. The results of the study will imply in a better knowledge about the effect of a low-cost intervention that could be easily replicated in outpatient care for the prevention and treatment of frailty, especially regarding the inflammatory and anti-inflammatory pathways involved in its pathophysiology. Brazilian Registry of Clinical Trials (RBR-9n5jbw; 01/24/2020). Registred January 2020. http://www.ensaiosclinicos.gov.br/rg/RBR-9n5jbw/ . Show less

Raising functional antibodies against G protein-coupled receptors (GPCRs) is challenging due to their low density expression, instability in the absence of the cell membrane's lipid bilayer and frequently short extracellular domains that can serve as antigens. In addition, a particular therapeutic concept may require an antibody to not just bind the receptor, but also act as a functional receptor agonist or antagonist. Antagonizing the glucose-dependent insulinotropic polypeptide (GIP) receptor may open up new therapeutic modalities in the treatment of diabetes and obesity. As such, a panel of monoclonal antagonistic antibodies would be a useful tool for in vitro and in vivo proof of concept studies. The receptor is highly conserved between rodents and humans, which has contributed to previous mouse and rat immunization campaigns generating very few usable antibodies. Switching the immunization host to chicken, which is phylogenetically distant from mammals, enabled the generation of a large and diverse panel of monoclonal antibodies containing 172 unique sequences. Three-quarters of all chicken-derived antibodies were functional antagonists, exhibited high-affinities to the receptor extracellular domain and sampled a broad epitope repertoire. For difficult targets, including GPCRs such as GIPR, chickens are emerging as valuable immunization hosts for therapeutic antibody discovery. Show less