Prevalence and spectrum of germline pathogenic variants in cancer susceptibility genes among mexican patients with exocrine pancreatic cancer.

BACKGROUND: Although universal germline genetic testing is recommended for patients with exocrine pancreatic cancer (PC), access to genetic testing remains limited in low- and middle-income countries. This study aims to narrow the gap in our understanding of the spectrum of germline pathogenic and likely pathogenic variants (PVs) in cancer susceptibility genes in the Mexican population. METHODS: The landscape of PVs in cancer susceptibility genes was identified by next-generation sequencing multigene panel assays among patients with PC who were enrolled in the Clinical Cancer Genomics Community Research Network prospective registry in Mexico City. RESULTS: From August 2019 to April 2023, 137 patients underwent genetic testing. The median age at diagnosis was 60 years (range 36-85), 58.4 % were women, and 38.7 % were metastatic at diagnosis. The frequency of germline PVs was 16 % (n = 22): ATM 36.4 % (n = 8), CDKN2A/p16INK4A 27.3 % (n = 6), BRCA2 9.1 % (n = 2), PALB2 9.1 % (n = 2), CHEK2 9.1 % (n = 2), TP53 4.5 % (n = 1), and NF1 4.5 % (n = 1). Additionally, 2 carriers of monoallelic germline variants in MUTYH were identified. No significant differences were observed between carriers and non-carriers in terms of family history of pancreatic cancer. CONCLUSIONS: We identified a significant frequency of actionable germline PVs in Mexicans with PC, wherein the majority were in a broad spectrum of genes associated with the homologous recombination DNA repair mechanism. Most pancreatic cancer associated PVs were detected in non-BRCA genes, so our findings support the recommendation of multigene panel testing for genetic cancer risk assessment of Mexican individuals with PC.

Subtotal versus total gastrectomy for distal diffuse-type gastric cancer.

INTRODUCTION: Diffuse-type gastric carcinoma in an aggressive form of gastric cancer. Surgery is the only potentially curative treatment. It is controversial whether patients with diffuse-type gastric carcinoma should undergo total or subtotal gastrectomy when feasible. The aim of this study is to analyze the oncologic outcomes and overall survival of patients diagnosed with distal diffuse-type gastric cancer undergoing subtotal versus total gastrectomy with curative intent. METHODS: This retrospective study included all patients with histologically confirmed diffuse-type distal gastric carcinoma and clinical staging cT1-4M0, who underwent surgery with curative intent between 2011 and 2020 in a Tertiary Referral Hospital in Chile. Clinical and pathological staging was conducted using the 8th Edition of the American Joint Committee on Cancer Classification. STG group was comprised by patients who underwent subtotal gastrectomy and TG group by patients who underwent total gastrectomy. Both groups were compared in relation to sociodemographic variables, pathology reports and perioperative data which were obtained from electronic medical records. Data analysis was obtained with Stata 16.1 Statistical Software. RESULTS: One hundred and thirty patients underwent curative intent surgery. Subtotal gastrectomy with D2-lymphadenectomy was completed in 68 patients (52%). An R0 resection was achieved in all patients. Median number of resected lymph nodes, tumor size, proximal margin and depth of invasion were similar in both groups. Pathologic staging was similar between both groups, the most frequent being Stage 3(54%). After a median follow-up of 47 months [0.3-157], no difference was observed in overall survival between both groups (5-year-OS 63% in STG group versus 51% in TG group, p = 0.097). CONCLUSIONS: Oncologic and survival outcomes were similar in patients submitted to subtotal and total gastrectomy, suggesting that a subtotal gastrectomy with D2-lymphadenectomy for distal diffuse-type gastric carcinoma is not associated with a decrease in median overall survival and is an adequate surgical approach when technically feasible.

Patient Navigation to Improve Early Access to Supportive Care for Patients with Advanced Cancer in Resource-Limited Settings: A Randomized Controlled Trial.

BACKGROUND: The early integration of supportive care in oncology improves patient-centered outcomes. However, data are lacking regarding how to achieve this in resource-limited settings. We studied whether patient navigation increased access to multidisciplinary supportive care among Mexican patients with advanced cancer. MATERIALS AND METHODS: This randomized controlled trial was conducted between August 2017 and April 2018 at a public hospital in Mexico City. Patients aged ≥18 years with metastatic tumors ≤6 weeks from diagnosis were randomized (1:1) to a patient navigation intervention or usual care. Patients randomized to patient navigation received personalized supportive care from a navigator and a multidisciplinary team. Patients randomized to usual care obtained supportive care referrals from treating oncologists. The primary outcome was the implementation of supportive care interventions at 12 weeks. Secondary outcomes included advance directive completion, supportive care needs, and quality of life. RESULTS: One hundred thirty-four patients were randomized: 67 to patient navigation and 67 to usual care. Supportive care interventions were provided to 74% of patients in the patient navigation arm versus 24% in usual care (difference 0.50, 95% confidence interval [CI] 0.34-0.62; p < .0001). In the patient navigation arm, 48% of eligible patients completed advance directives, compared with 0% in usual care (p < .0001). At 12 weeks, patients randomized to patient navigation had less moderate/severe pain (10% vs. 33%; difference 0.23, 95% CI 0.07-0.38; p = .006), without differences in quality of life between arms. CONCLUSION: Patient navigation improves access to early supportive care, advance care planning, and pain for patients with advanced cancer in resource-limited settings. IMPLICATIONS FOR PRACTICE: The early implementation of supportive care in oncology is recommended by international guidelines, but this might be difficult to achieve in resource-limited settings. This randomized clinical trial including 134 Mexican patients with advanced cancer demonstrates that a multidisciplinary patient navigation intervention can improve the early access to supportive and palliative care interventions, increase advance care planning, and reduce symptoms compared with usual oncologist-guided care alone. These results demonstrate that patient navigation represents a potentially useful solution to achieve the adequate implementation of supportive and palliative care in resource-limited settings globally.

Pediatric asthma treatment: What to do when international guideline recommendations do not agree.

BACKGROUND: There was a need for a solid asthma guideline in Mexico to update and unify asthma management. Because high-quality asthma guidelines exist worldwide, in which the latest evidence on asthma management is summarized, the ADAPTE approach allows for the development of a national asthma guideline based on evidence from already existing guidelines, adapted to national needs. OBJECTIVE: To fuse evidence from the best asthma guidelines and adapt it to local needs with the ADAPTE approach. METHODS: The Appraisal of Guidelines for Research and Evaluation (AGREE) II asthma guidelines were evaluated by a core group to select 3 primary guidelines. For each step of asthma management, clinical questions were formulated and replied according to (1) evidence in the primary guidelines, (2) safety, (3) Cost, and (4) patient preference. The Guidelines Development Group, composed of a broad range of experts from medical specialties, primary care physicians, and methodologists, adjusted the draft questions and replies in several rounds of a Delphi process and 3 face-to-face meetings, taking into account the reality of the situation in Mexico. We present the results of the pediatric asthma treatment part. RESULTS: Selected primary guidelines are from the British Thoracic Society and Scottish Intercollegiate Guidelines Network (BTS/SIGN), Global Initiative for Asthma (GINA), and Spanish Guidelines on the Management of Asthma (GEMA) 2015, with 2016 updates. Recommendations or suggestions were made for asthma treatment in Mexico. In this article, the detailed analysis of the evidence present in the BTS/SIGN, GINA, and GEMA sections on the (non) pharmacologic treatment of pediatric asthma, education, and devices are presented for 2 age groups: children 5 years or younger and children 6 to 11 years old with asthma. CONCLUSION: For the pediatric treatment and patient education sections, applying the AGREE II and Delphi methods is useful to develop a scientifically sustained document, adjusted to the Mexican situation, as is the Mexican Guideline on Asthma.

Effect of cholecystectomy on bile acid synthesis and circulating levels of fibroblast growth factor 19.

UNLABELLED: Background and rationale for the study. FGF19/15 is a gut-derived hormone presumably governing bile acid (BA) synthesis and gallbladder (GB) refilling. FGF19 mRNA is present in human GB cholangiocytes (hGBECs); however, the physiological significance of GB-derived FGF19 remains unknown. We investigated whether hGBECs secrete FGF19 and the effects of cholecystectomy on serum FGF19 ([FGF19]s) and BA synthesis. MATERIAL AND METHODS: FGF19 expression was assessed by qRT-PCRs and immunostaining in hGBECs and terminal ileum, and quantified in bile and serum by ELISA. Basal and BA (chenodexycholic acid, CDCA) induced FGF19 expression and secretion was analyzed in primary cultured hGBECs and GB-d1 cell line. Pre and postprandial serum changes in [FGF19]s, 7α-hydroxy-4-cholestene-3-one (C4, a marker of BA synthesis) and BA were evaluated in plasma of gallstone disease patients at baseline and after cholecystectomy. RESULTS: FGF19 mRNA levels were ~250-fold higher in hGBECs compared to distal ileum. GB bile contained ~23-fold higher FGF19 levels compared to serum (p < 0.0001). CDCA induced dose-dependent expression and secretion of FGF19 in hGBECs and GB-d1 cells. Cholecystectomy increased plasma BA synthesis ≥ 2-fold (p < 0.0001), and altered the diurnal rhythm and significantly reduced [FGF19]s noon peak. BA serum levels, serum cholesterol and triglyceride content remained unchanged. CONCLUSIONS: In conclusion human GB cholangiocytes constitutively express and secrete high levels of FGF19 in a process regulated by BA. Resection of this organ doubles BA synthesis concomitantly with changes in [FGF19]s. These findings suggest a potential connection between GB cholangiocytes-derived FGF19 and BA metabolism that could lead to metabolic dysregulation following cholecystectomy.

Genetic and functional identification of the likely causative variant for cholesterol gallstone disease at the ABCG5/8 lithogenic locus.

UNLABELLED: The sterolin locus (ABCG5/ABCG8) confers susceptibility for cholesterol gallstone disease in humans. Both the responsible variant and the molecular mechanism causing an increased incidence of gallstones in these patients have as yet not been identified. Genetic mapping utilized patient samples from Germany (2,808 cases, 2,089 controls), Chile (680 cases, 442 controls), Denmark (366 cases, 766 controls), India (247 cases, 224 controls), and China (280 cases, 244 controls). Analysis of allelic imbalance in complementary DNA (cDNA) samples from human liver (n = 22) was performed using pyrosequencing. Transiently transfected HEK293 cells were used for [(3) H]-cholesterol export assays, analysis of protein expression, and localization of allelic constructs. Through fine mapping in German and Chilean samples, an ∼250 kB disease-associated interval could be defined for this locus. Lack of allelic imbalance or allelic splicing of the ABCG5 and ABCG8 transcripts in human liver limited the search to coding single nucleotide polymorphisms. Subsequent mutation detection and genotyping yielded two disease-associated variants: ABCG5-R50C (P = 4.94 × 10(-9) ) and ABCG8-D19H (P = 1.74 × 10(-10) ) in high pairwise linkage disequilibrium (r(2) = 0.95). [(3) H]-cholesterol export assays of allelic constructs harboring these genetic candidate variants demonstrated increased transport activity (3.2-fold, P = 0.003) only for the ABCG8-19H variant, which was also superior in nested logistic regression models in German (P = 0.018), Chilean (P = 0.030), and Chinese (P = 0.040) patient samples. CONCLUSION: This variant thus provides a molecular basis for biliary cholesterol hypersecretion as the mechanism for cholesterol gallstone formation, thereby drawing a link between "postgenomic" and "pregenomic" pathophysiological knowledge about this common complex disorder. (HEPATOLOGY 2012).

Optimization of lung tissue pre-treatment by bead homogenization for subsequent culturomics.

The discovery that the lung harbors a diverse microbiome, as revealed by next-generation sequencing, has significantly altered our understanding of respiratory health and disease. Despite the association between the lung microbiota and disease, the nature of their relationship remains poorly understood, and culture isolation of these microorganisms could help to determine their role in lung physiology. Current procedures for processing samples from the lower respiratory tract have been shown to affect the viability of microorganisms, so it is crucial to develop new methods to improve their survival. This study aimed to improve the isolation and characterization of lung microorganisms using a bead-beating homogenization method in a mouse model. Microsphere diameter and bead-beating time affected the survival of the microorganisms (E. coli, S. aureus and C. albicans). Using 2.3 mm diameter microspheres for 60 s of bead-beating promoted the survival of both bacteria and yeast strains. After intratracheal instillation of these microorganisms in mice, approximately 70% of the cells were recovered after the tissue homogenization. To assess the efficiency of the proposed method, the diversity of bacteria was compared between the homogenate and lung tissue samples. Ninety-one genera were detected in the lung tissue, and 63 in the homogenate. Bacterial genera detected in the homogenate represented 84% of the total abundance of the microbiota identified in the lung tissue. Taken together, these results demonstrate that the tissue homogenization process developed in this study recovered the majority of the microorganisms present in the lung. This study presents a bead-beating homogenization method for effective cultivation of lung tissue microorganisms, which may help to improve the understanding of host-microbe interactions in the lung.

[Prevalence of Gilbert syndrome and its genetic determinants in Chile]. / Prevalencia de síndrome de Gilbert y sus determinantes genéticas en población chilena.

BACKGROUND: In Europeans the TATA box TA7 repeat promoter variant in the UGT1A1 gene (UGT1A1*28) is the major determinant of bilirubin levels. AIM: To study the prevalence of Gilbert Syndrome (GS) and its genetic determinants in Chile. MATERIAL AND METHODS: Three different studies were conducted. The prevalence of GS in Chile was assessed in 991 subjects with normal liver tests (ALT and GGT) from the 2nd National Health Survey. We defined GS as a total bilirubin (TB) between 1.4-5mg/dL. The second study assessed the genotype prevalence of SNP rs6742078 (in LD with UGT1A1*28) and rs4149056 in 500 DNA samples of non-related Hispanics. Finally, a case-control study was designed to assess the phenotype-genotype correlation. UGT1A1*28 and rs4149056 variants were determined by direct sequencing and allelic discrimination assays (TaqMan), respectively. RESULTS: Prevalence of GS in the general Chilean population was 2.6% (4.5% in males and 0.5% in female). No correlation with age, educational level or home location was found. Genotypes for UGT1A1*28 (TA6/6 50.5%, TA6/7 37.8%, TA7/7 11.7%) and rs4149056 (TT 74.1%, CT 22.8%, and CC 3.1%) variants were similar to Europeans. In the case-control study, most patients with GS were homozygotes for UGT1A1*28 (TA7/7, 74%). Of note, 44% of patients with intermediate TB levels were also TA7/7, compared to 7% in normal subjects. SLCO1B1 genotype was not correlated with TB levels. CONCLUSIONS: While the prevalence of GS was lower in Chile compared to Europeans (~5%), the prevalence of UGT1A1*28 homozygotes was similar (~12%). In Chilean Hispanics, the UGT1A1*28 variant explain 75% of GS phenotype.

Fluctuations in Seminal Quality throughout the Year: How do Temperature, Humidity and Atmospheric Pressure Impact on Human Sperm Quality?

Background: Most studies evaluating the possible seasonal variation of semen quality have considered temperature as the only causal factor. Aims: To assess possible seasonality in sperm quality and associations between semen parameters and several meteorological variables (temperature, humidity, apparent temperature and atmospheric pressure) in a large cohort of andrological patients. Settings and Design: This was a retrospective, cross-sectional and correlational/descriptive study. Materials and Methods: Patients (n: 15665) were categorised into four groups (summer, winter, spring and autumn) according to the date of assistance at the fertility centre. Daily values of temperature, apparent temperature, humidity and atmospheric pressure were provided by the National Weather System and were calculated as the average of the 74 days previous to semen collection (spermatogenic cycle). Statistical Analysis Used: As appropriate, the results were analysed by analysis of variance/Kruskal-Wallis, Chi-square test, t-test/Mann-Whitney, forward conditional regression model and Spearman/Pearson's correlations. Results: We detected seasonality effects on sperm count, total sperm count and total motile sperm count, with the highest values in winter and the lowest in summer. Correlation analysis showed that temperature, apparent temperature and humidity negatively correlated with semen parameters, being humidity the most powerful predictive meteorological variable. Conclusion: Sperm quality is influenced by seasons; increased environmental temperature and humidity negatively affect semen quality.

Right-sided acute diverticulitis in the West: experience at a university hospital in Argentina.

PURPOSE: In the West, diverticular disease is located mainly in the left colon. However, it can also present in the right colon, with an incidence of 1% to 2% in Caucasians. The purpose of this study was to describe our experience in right-sided acute diverticulitis (RD). METHODS: In this retrospective study, 410 patients with acute diverticulitis treated from 2013 to 2020 were included in a university hospital in Córdoba, Argentina. Colonic diverticulitis was stratified into 2 groups; RD and left-sided acute diverticulitis. Demographic and clinical variables, laboratory and imaging findings, type of treatment, follow-up, and recurrence were analyzed. RESULTS: Sixteen patients (3.9%) with RD were identified; 62.5% were male and the mean age was 40.7±11.7 years. A total of 81.3% were Caucasian and 18.7% Native American. Significant differences were found between both groups of diverticulitis; patients with RD were younger (P=0.001), with lower BMI (P=0.01), comorbidity rate (P=0.01), Charlson comorbidity index (P=0.02), hospital stay (P=0.01), severity according to the Hinchey classification (P=0.001) and had a lower recurrence rate (P=0.001). There were no significant differences in sex (P=0.95), duration of pain until admission (P=0.05), laboratory findings (P=0.23) and treatment (P=0.34). CONCLUSION: Conservative treatment predominated in RD, with a lower rate of complications and recurrences, providing data that support conservative therapy as initial treatment in RD in our environment.

Complement receptor 2 is expressed in neural progenitor cells and regulates adult hippocampal neurogenesis.

Injury and inflammation are potent regulators of adult neurogenesis. As the complement system forms a key immune pathway that may also exert critical functions in neural development and neurodegeneration, we asked whether complement receptors regulate neurogenesis. We discovered that complement receptor 2 (CR2), classically known as a coreceptor of the B-lymphocyte antigen receptor, is expressed in adult neural progenitor cells (NPCs) of the dentate gyrus. Two of its ligands, C3d and interferon-α (IFN-α), inhibited proliferation of wild-type NPCs but not NPCs derived from mice lacking Cr2 (Cr2(-/-)), indicating functional Cr2 expression. Young and old Cr2(-/-) mice exhibited prominent increases in basal neurogenesis compared with wild-type littermates, whereas intracerebral injection of C3d resulted in fewer proliferating neuroblasts in wild-type than in Cr2(-/-) mice. We conclude that Cr2 regulates hippocampal neurogenesis and propose that increased C3d and IFN-α production associated with brain injury or viral infections may inhibit neurogenesis.

The complement inhibitors Crry and factor H are critical for preventing autologous complement activation on renal tubular epithelial cells.

Congenital and acquired deficiencies of complement regulatory proteins are associated with pathologic complement activation in several renal diseases. To elucidate the mechanisms by which renal tubular epithelial cells (TECs) control the complement system, we examined the expression of complement regulatory proteins by the cells. We found that Crry is the only membrane-bound complement regulator expressed by murine TECs, and its expression is concentrated on the basolateral surface. Consistent with the polarized localization of Crry, less complement activation was observed when the basolateral surface of TECs was exposed to serum than when the apical surface was exposed. Furthermore, greater complement activation occurred when the basolateral surface of TECs from Crry(-/-)fB(-/-) mice was exposed to normal serum compared with TECs from wild-type mice. Complement activation on the apical and basolateral surfaces was also greater when factor H, an alternative pathway regulatory protein found in serum, was blocked from interacting with the cells. Finally, we injected Crry(-/-)fB(-/-) and Crry(+/+)fB(-/-) mice with purified factor B (an essential protein of the alternative pathway). Spontaneous complement activation was seen on the tubules of Crry(-/-)fB(-/-) mice after injection with factor B, and the mice developed acute tubular injury. These studies indicate that factor H and Crry regulate complement activation on the basolateral surface of TECs and that factor H regulates complement activation on the apical surface. However, congenital deficiency of Crry or reduced expression of the protein on the basolateral surface of injured cells permits spontaneous complement activation and tubular injury.

Regulation of the Intestinal Extra-Adrenal Steroidogenic Pathway Component LRH-1 by Glucocorticoids in Ulcerative Colitis.

Ulcerative colitis (UC) is an inflammatory bowel disease (IBD) and can be treated with glucocorticoids (GC), although some patients are unresponsive to this therapy. The transcription factor LRH-1/NR5A2 is critical to intestinal cortisol production (intestinal steroidogenesis), being reduced in UC patients. However, the relationship between LRH-1 expression and distribution with altered corticosteroid responses is unknown. To address this, we categorized UC patients by their steroid response. Here, we found that steroid-dependent and refractory patients presented reduced glucocorticoid receptor (GR)-mediated intestinal steroidogenesis compared to healthy individuals and responder patients, possibly related to increased colonic mucosa GR isoform beta (GRß) content and cytoplasmic LRH-1 levels in epithelial and lamina propria cells. Interestingly, an intestinal epithelium-specific GR-induced knockout (GRiKO) dextran sodium sulfate (DSS)-colitis mice model presented decreased epithelial LRH-1 expression, whilst it increased in the lamina propria compared to DSS-treated control mice. Mechanistically, GR directly induced NR5A2 gene expression in CCD841CoN cells and human colonic organoids. Furthermore, GR bound to two glucocorticoid-response elements within the NR5A2 promoter in dexamethasone-stimulated CCD841CoN cells. We conclude that GR contributes to intestinal steroidogenesis by inducing LRH-1 in epithelial cells, suggesting LRH-1 as a potential marker for glucocorticoid-impaired response in UC. However, further studies with a larger patient cohort will be necessary to confirm role of LRH-1 as a therapeutic biomarker.

Tolerance is dependent on complement C3 fragment iC3b binding to antigen-presenting cells.

Systemic tolerance can be induced by the introduction of antigen into an immune-privileged site. Here we investigated the role of complement in the induction of tolerance after intraocular injection. We found that the development of antigen-specific tolerance is dependent on a complement activation product. The ligation of the complement C3 activation product iC3b to complement receptor type 3 (the iC3b receptor) on antigen-presenting cells resulted in the sequential production of transforming growth factor-beta2 and interleukin-10, which is essential for the induction of tolerance. These observations may extend to the development of both neonatal tolerance and other forms of acquired tolerance.

[MIA 2021, Comprehensive Asthma Management. Guidelines for Mexico]. / MIA 2021, Manejo Integral del Asma. Lineamientos para México.

BACKGROUND: Asthma continues to be one of the most frequent chronic respiratory diseases in our country. New methods for diagnosis and treatment have been described; accordingly, the international guidelines were renewed. OBJECTIVE: To create a national platform for the development of updated guidelines, solidly based on evidence: Comprehensive Asthma Management (Spanish acronym: MIA). METHODS: MIA uses the ADAPTE method. The MIA development group consists of experts in pulmonology-allergology-methodology and representatives of 13 institutions and societies of specialties that manage asthma. The international reference guidelines (selected with AGREE-II): GINA 2020, GEMA 5.0, BTS/SIGN 2019 and ATS/ERS consensus document 2014-2019 on severe asthma. MIA covers suspected asthma, diagnosis, treatment, and special groups. Key clinical questions were formulated on treatment steps 1-3, biomarkers and severe asthma. RESULTS: Based on evidence, safety, cost and local reality, the core group developed responses. Through a Delphi process the broad MIA development group suggested adjustments until consensus was reached. CONCLUSION: A document was generated with multiple figures and algorithms, solidly based on evidence about asthma management, adjusted for Mexico with a broad base among different societies that participated in its development. It does not include guidelines for acute asthma.

Antecedentes: El asma sigue siendo una patología respiratoria crónica frecuente en México. Se han descrito nuevos métodos para el diagnóstico y tratamiento conforme se renuevan las guías internacionales. Objetivo: Crear la plataforma nacional Manejo Integral del Asma (MIA), para el desarrollo de lineamientos actualizados con base en evidencia. Métodos: Se utilizó el método ADAPTE. El grupo de desarrollo de MIA estuvo integrado por expertos en neumología, alergología y metodología y representantes de 13 instituciones y sociedades de especialidades que manejan asma. Las guías internacionales de referencia (seleccionadas con AGREE-II) fueron GINA 2020, GEMA 5.0, BTS/SIGN 2019 y consenso ATS/ERS 2014-2019. En MIA se aborda sospecha de asma, diagnóstico, tratamiento y grupos especiales. Se formularon preguntas clínicas clave sobre tratamiento en los pasos 1 a 3, biomarcadores y asma grave. Resultados: Con base en evidencia, seguridad, costo y realidad local, el grupo nuclear desarrolló respuestas. Mediante proceso Delphi, el grupo amplio de desarrollo sugirió ajustes hasta que se logró el consenso. Conclusión: El documento generado contiene múltiples figuras y algoritmos, está sólidamente basado en evidencia acerca del manejo del asma y fue ajustado para México con participación de diferentes sociedades para su desarrollo; no se incluyeron lineamientos para la crisis asmática.

Complement C3 activation is required for antiphospholipid antibody-induced fetal loss.

The antiphospholipid syndrome (APS) is characterized by recurrent fetal loss, vascular thrombosis, and thrombocytopenia occurring in the presence of antiphospholipid (aPL) antibodies. The pathogenesis of fetal loss and tissue injury in APS is incompletely understood, but is thought to involve platelet and endothelial cell activation as well as procoagulant effects of aPL antibodies acting directly on clotting pathway components. Recent studies have shown that uncontrolled complement activation in the placenta leads to fetal death in utero. We hypothesized that aPL antibodies activate complement in the placenta, generating split products that mediate placental injury and lead to fetal loss and growth retardation. To test this hypothesis, we used a murine model of APS in which pregnant mice are injected with human IgG containing aPL antibodies. We found that inhibition of the complement cascade in vivo, using the C3 convertase inhibitor complement receptor 1-related gene/protein y (Crry)-Ig, blocks fetal loss and growth retardation. Furthermore, mice deficient in complement C3 were resistant to fetal injury induced by aPL antibodies. While antigenic epitopes recognized by aPL antibodies are important in the pathogenesis of APS, our data show that in vivo complement activation is required for aPL antibody-induced fetal loss and growth retardation.

Deficiency of Niemann-Pick C1 protein protects against diet-induced gallstone formation in mice.

BACKGROUND/AIMS: Receptor-mediated endocytosis is a critical cellular mechanism for the uptake of lipoprotein cholesterol in the liver. Because Niemann-Pick C1 (NPC1) protein is a key component for the intracellular distribution of cholesterol originating from lipoprotein endocytosis, it may play an important role in controlling biliary cholesterol secretion and gallstone formation induced by a lithogenic diet. METHODS: We studied biliary cholesterol secretion, gallbladder lipid composition and gallstone formation in NPC1-deficient mice fed a low-fat lithogenic diet (1.5% cholesterol and 0.5% cholic acid) compared with control animals under the same diet. RESULTS: The lipid secretion response to the lithogenic diet was impaired in NPC1 (-/-) mice, leading to a decreased cholesterol output and an increased hepatic cholesterol concentration compared with the lithogenic diet-fed wild-type mice. A decreased cholesterol saturation index was found in the gallbladder bile of NPC1 (+/-) and (-/-) mice after lithogenic diet feeding. Consequently, mice with a partial or a total deficiency of NPC1 had a drastically lower frequency of gallbladder cholesterol crystals and a reduced prevalence of gallstones. CONCLUSION: Hepatic NPC1 expression is an important factor for regulating the biliary secretion of diet-derived cholesterol as well as for diet-induced cholesterol gallstone formation in mice.

Membrane protein Crry maintains homeostasis of the complement system.

Complement activation is tightly regulated to avoid excessive inflammatory and immune responses. Crry(-/-) is an embryonic lethal phenotype secondary to the maternal complement alternative pathway (AP) attacking a placenta deficient in this inhibitor. In this study, we demonstrate that Crry(-/-) mice could be rescued on a partial as well as on a complete factor B (fB)- or C3-deficient maternal background. The C3 and fB protein concentrations in Crry(-/-)C3(+/-) and Crry(-/-)fB(+/-) mice were substantially reduced for gene dosage secondary to enhanced AP turnover. Based on these observations, a breeding strategy featuring reduced maternal AP-activating capacity rescued the lethal phenotype. It led to a novel, stable line of Crry SKO mice carrying normal alleles for C3 and fB. Crry SKO mice also had accelerated C3 and fB turnover and therefore reduced AP- activating potential. These instructive results represent an example of a membrane regulatory protein being responsible for homeostasis of the complement system. They imply that there is constant turnover on cells of the AP pathway which functions as an immune surveillance system for pathogens and altered self.

Transcriptomic profiles reveal differences in zinc metabolism, inflammation, and tight junction proteins in duodenum from cholesterol gallstone subjects.

Cholesterol Gallstone Disease (GSD) is a common multifactorial disorder characterized by crystallization and aggregation of biliary cholesterol in the gallbladder. The global prevalence of GSD is ~10-20% in the adult population but rises to 28% in Chile (17% among men and 30% among women). The small intestine may play a role in GSD pathogenesis, but the molecular mechanisms have not been clarified. Our aim was to identify the role of the small intestine in GSD pathogenesis. Duodenal biopsy samples were obtained from patients with GSD and healthy volunteers. GSD status was defined by abdominal ultrasonography. We performed a transcriptome study in a discovery cohort using Illumina HiSeq. 2500, and qPCR, immunohistochemistry and immunofluorescence were used to validate differentially expressed genes among additional case-control cohorts. 548 differentially expressed genes between GSD and control subjects were identified. Enriched biological processes related to cellular response to zinc, and immune and antimicrobial responses were observed in GSD patients. We validated lower transcript levels of metallothionein, NPC1L1 and tight junction genes and higher transcript levels of genes involved in immune and antimicrobial pathways in GSD patients. Interestingly, serum zinc and phytosterol to cholesterol precursor ratios were lower in GSD patients. A significant association was observed between serum zinc and phytosterol levels. Our results support a model where proximal small intestine plays a key role in GSD pathogenesis. Zinc supplementation, modulation of proximal microbiota and/or intestinal barrier may be novel targets for strategies to prevent GSD.