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2.
J Allergy Clin Immunol ; 152(3): 799-806.e6, 2023 09.
Article in English | MEDLINE | ID: mdl-37301411

ABSTRACT

BACKGROUND: The upper-airway microbiome is involved in asthma exacerbations despite inhaled corticosteroid (ICS) treatment. Although human genetics regulates microbiome composition, its influence on asthma-related airway bacteria remains unknown. OBJECTIVE: We sought to identify genes and biological pathways regulating airway-microbiome traits involved in asthma exacerbations and ICS response. METHODS: Saliva, nasal, and pharyngeal samples from 257 European patients with asthma were analyzed. The association of 6,296,951 genetic variants with exacerbation-related microbiome traits despite ICS treatment was tested through microbiome genome-wide association studies. Variants with 1 × 10-4 

Subject(s)
Anti-Asthmatic Agents , Asthma , Humans , Anti-Asthmatic Agents/therapeutic use , Genome-Wide Association Study , NF-kappa B/genetics , Administration, Inhalation , Asthma/drug therapy , Asthma/genetics , Adrenal Cortex Hormones/therapeutic use , Human Genetics , Cytidine Deaminase , Minor Histocompatibility Antigens , Carrier Proteins/genetics
3.
Pulmonology ; 2023 May 24.
Article in English | MEDLINE | ID: mdl-37236906

ABSTRACT

INTRODUCTION AND OBJECTIVES: Asthma is a chronic inflammatory disease of the airways. Asthma patients may experience potentially life-threatening episodic flare-ups, known as exacerbations, which may significantly contribute to the asthma burden. The Pi*S and Pi*Z variants of the SERPINA1 gene, which usually involve alpha-1 antitrypsin (AAT) deficiency, had previously been associated with asthma. The link between AAT deficiency and asthma might be represented by the elastase/antielastase imbalance. However, their role in asthma exacerbations remains unknown. Our objective was to assess whether SERPINA1 genetic variants and reduced AAT protein levels are associated with asthma exacerbations. MATERIALS AND METHODS: In the discovery analysis, SERPINA1 Pi*S and Pi*Z variants and serum AAT levels were analyzed in 369 subjects from La Palma (Canary Islands, Spain). As replication, genomic data from two studies focused on 525 Spaniards and publicly available data from UK Biobank, FinnGen, and GWAS Catalog (Open Targets Genetics) were analyzed. The associations between SERPINA1 Pi*S and Pi*Z variants and AAT deficiency with asthma exacerbations were analyzed with logistic regression models, including age, sex, and genotype principal components as covariates. RESULTS: In the discovery, a significant association with asthma exacerbations was found for both Pi*S (odds ratio [OR]=2.38, 95% confidence interval [CI]= 1.40-4.04, p-value=0.001) and Pi*Z (OR=3.49, 95%CI=1.55-7.85, p-value=0.003)Likewise, AAT deficiency was associated with a higher risk for asthma exacerbations (OR=5.18, 95%CI=1.58-16.92, p-value=0.007) as well as AAT protein levels (OR= 0.72, 95%CI=0.57-0.91, p-value=0.005). The Pi*Z association with exacerbations was replicated in samples from Spaniards with two generations of Canary Islander origin (OR=3.79, p-value=0.028), and a significant association with asthma hospitalizations was found in the Finnish population (OR=1.12, p-value=0.007). CONCLUSIONS: AAT deficiency could be a potential therapeutic target for asthma exacerbations in specific populations.

5.
J Allergy Clin Immunol ; 151(3): 706-715, 2023 03.
Article in English | MEDLINE | ID: mdl-36343772

ABSTRACT

BACKGROUND: The response to inhaled corticosteroids (ICS) in asthma is affected by the interplay of several factors. Among these, the role of the upper-airway microbiome has been scarcely investigated. We aimed to evaluate the association between the salivary, pharyngeal, and nasal microbiome with asthma exacerbations despite receipt of ICS. METHODS: Samples from 250 asthma patients from the Genomics and Metagenomics of Asthma Severity (GEMAS) study treated with ICS were analyzed. Control/case subjects were defined by the absence/presence of asthma exacerbations in the past 6 months despite being treated with ICS. The bacterial microbiota was profiled by sequencing the V3-V4 region of the 16S rRNA gene. Differences between groups were assessed by PERMANOVA and regression models adjusted for potential confounders. A false discovery rate (FDR) of 5% was used to correct for multiple comparisons. Classification models of asthma exacerbations despite ICS treatment were built with machine learning approaches based on clinical, genetic, and microbiome data. RESULTS: In nasal and saliva samples, case subjects had lower bacterial diversity (Richness, Shannon, and Faith indices) than control subjects (.007 ≤ P ≤ .037). Asthma exacerbations accounted for 8% to 9% of the interindividual variation of the salivary and nasal microbiomes (.003 ≤ P ≤ .046). Three, 4, and 11 bacterial genera from the salivary, pharyngeal, and nasal microbiomes were differentially abundant between groups (4.09 × 10-12 ≤ FDR ≤ 0.047). Integrating clinical, genetic, and microbiome data showed good discrimination for the development of asthma exacerbations despite receipt of ICS (AUCtraining: 0.82 and AUCvalidation: 0.77). CONCLUSION: The diversity and composition of the upper-airway microbiome are associated with asthma exacerbations despite ICS treatment. The salivary microbiome has a potential application as a biomarker of asthma exacerbations despite receipt of ICS.


Subject(s)
Anti-Asthmatic Agents , Asthma , Microbiota , Humans , Anti-Asthmatic Agents/therapeutic use , RNA, Ribosomal, 16S , Administration, Inhalation , Asthma/drug therapy , Adrenal Cortex Hormones/therapeutic use , Biomarkers
6.
Thorax ; 78(3): 233-241, 2023 03.
Article in English | MEDLINE | ID: mdl-36180068

ABSTRACT

BACKGROUND: In the USA, genetically admixed populations have the highest asthma prevalence and severe asthma exacerbations rates. This could be explained not only by environmental factors but also by genetic variants that exert ethnic-specific effects. However, no admixture mapping has been performed for severe asthma exacerbations. OBJECTIVE: We sought to identify genetic variants associated with severe asthma exacerbations in Hispanic/Latino subgroups by means of admixture mapping analyses and fine mapping, and to assess their transferability to other populations and potential functional roles. METHODS: We performed an admixture mapping in 1124 Puerto Rican and 625 Mexican American children with asthma. Fine-mapping of the significant peaks was performed via allelic testing of common and rare variants. We performed replication across Hispanic/Latino subgroups, and the transferability to non-Hispanic/Latino populations was assessed in 1001 African Americans, 1250 Singaporeans and 941 Europeans with asthma. The effects of the variants on gene expression and DNA methylation from whole blood were also evaluated in participants with asthma and in silico with data obtained through public databases. RESULTS: Genomewide significant associations of Indigenous American ancestry with severe asthma exacerbations were found at 5q32 in Mexican Americans as well as at 13q13-q13.2 and 3p13 in Puerto Ricans. The single nucleotide polymorphism (SNP) rs1144986 (C5orf46) showed consistent effects for severe asthma exacerbations across Hispanic/Latino subgroups, but it was not validated in non-Hispanics/Latinos. This SNP was associated with DPYSL3 DNA methylation and SCGB3A2 gene expression levels. CONCLUSIONS: Admixture mapping study of asthma exacerbations revealed a novel locus that exhibited Hispanic/Latino-specific effects and regulated DPYSL3 and SCGB3A2.


Subject(s)
Asthma , Hispanic or Latino , Adolescent , Humans , Asthma/genetics , Genome-Wide Association Study , Hispanic or Latino/genetics , Polymorphism, Single Nucleotide , United States/epidemiology , Child , Mexican Americans
7.
Front Pediatr ; 10: 985892, 2022.
Article in English | MEDLINE | ID: mdl-36186645

ABSTRACT

Alpha-1-antitrypsin deficiency (AATD) is a heritable condition that predisposes to respiratory and hepatic complications. Screenings in East Asia human populations for the AATD alleles most commonly found among Caucasians have yielded poor outcomes. Serum alpha-1-antitrypsin (AAT) levels, AAT phenotypes, and sequences of SERPINA1 gene were examined in a Chinese child with a moderate deficit of serum AAT, who had suffered several episodes of liver disease, as well as in his first-order relatives. Results allowed the identification of PI * S hangzhou , a novel SERPINA1 defective allele, which has been characterized by a L276R substitution, found in a SERPINA1-M3 genetic background. Moreover, potential effects of PI * S hangzhou mutation over the AAT structure were studied by 3D homology modeling. The presence of an arginine residue at position 276 could destabilize the tertiary structure of AAT, since it occurs at a highly conserved hydrophobic cavity in the protein surface, and very close to two positively-charged lysine residues. Attending to the frequency of R276 variant reported in databases for individuals of East Asian ancestry, the PI * S hangzhou allele may explain the global prevalence of the PiS phenotype observed in China.

8.
Pediatr Allergy Immunol ; 33(6): e13802, 2022 06.
Article in English | MEDLINE | ID: mdl-35754128

ABSTRACT

BACKGROUND: Asthma exacerbations are a serious public health concern due to high healthcare resource utilization, work/school productivity loss, impact on quality of life, and risk of mortality. The genetic basis of asthma exacerbations has been studied in several populations, but no prior study has performed a multi-ancestry meta-analysis of genome-wide association studies (meta-GWAS) for this trait. We aimed to identify common genetic loci associated with asthma exacerbations across diverse populations and to assess their functional role in regulating DNA methylation and gene expression. METHODS: A meta-GWAS of asthma exacerbations in 4989 Europeans, 2181 Hispanics/Latinos, 1250 Singaporean Chinese, and 972 African Americans analyzed 9.6 million genetic variants. Suggestively associated variants (p ≤ 5 × 10-5 ) were assessed for replication in 36,477 European and 1078 non-European asthma patients. Functional effects on DNA methylation were assessed in 595 Hispanic/Latino and African American asthma patients and in publicly available databases. The effect on gene expression was evaluated in silico. RESULTS: One hundred and twenty-six independent variants were suggestively associated with asthma exacerbations in the discovery phase. Two variants independently replicated: rs12091010 located at vascular cell adhesion molecule-1/exostosin like glycosyltransferase-2 (VCAM1/EXTL2) (discovery: odds ratio (ORT allele ) = 0.82, p = 9.05 × 10-6 and replication: ORT allele  = 0.89, p = 5.35 × 10-3 ) and rs943126 from pantothenate kinase 1 (PANK1) (discovery: ORC allele  = 0.85, p = 3.10 × 10-5 and replication: ORC allele  = 0.89, p = 1.30 × 10-2 ). Both variants regulate gene expression of genes where they locate and DNA methylation levels of nearby genes in whole blood. CONCLUSIONS: This multi-ancestry study revealed novel suggestive regulatory loci for asthma exacerbations located in genomic regions participating in inflammation and host defense.


Subject(s)
Asthma , Genome-Wide Association Study , Asthma/genetics , Genetic Predisposition to Disease , Hispanic or Latino/genetics , Humans , Polymorphism, Single Nucleotide , Quality of Life
9.
J Pers Med ; 10(3)2020 Sep 11.
Article in English | MEDLINE | ID: mdl-32933076

ABSTRACT

Asthma exacerbations are a major contributor to the global disease burden, but no significant predictive biomarkers are known. The Genomics and Metagenomics of Asthma Severity (GEMAS) study aims to assess the role of genomics and the microbiome in severe asthma exacerbations. Here, we present the design of GEMAS and the characteristics of patients recruited from March 2018 to March 2020. Different biological samples and demographic and clinical variables were collected from asthma patients recruited by allergy and pulmonary medicine units in several hospitals from Spain. Cases and controls were defined by the presence/absence of severe asthma exacerbations in the past year (oral corticosteroid use, emergency room visits, and/or asthma-related hospitalizations). A total of 137 cases and 120 controls were recruited. After stratifying by recruitment location (i.e., Canary Islands and Basque Country), cases and controls did not differ for most demographic and clinical variables (p > 0.05). However, cases showed a higher proportion of characteristics inherent to asthma exacerbations (impaired lung function, severe disease, uncontrolled asthma, gastroesophageal reflux, and use of asthma medications) compared to controls (p < 0.05). Similar results were found after stratification by recruitment unit. Thereby, asthma patients enrolled in GEMAS are balanced for potential confounders and have clinical characteristics that support the phenotype definition. GEMAS will improve the knowledge of potential biomarkers of asthma exacerbations.

10.
Rev. esp. salud pública ; 94: 0-0, 2020. tab, graf
Article in Spanish | IBECS | ID: ibc-200459

ABSTRACT

El Programa de Cribado Neonatal de Cataluña (PCNC) se inició en el año 1969, en Barcelona, impulsado por el Dr. Juan Sabater Tobella y apoyado por la Diputación de Barcelona y la Fundación Juan March. Así nació el Instituto de Bioquímica Clínica para acometer funciones asistenciales, de investigación y docencia, con el espíritu de contribuir a la prevención del retraso mental. El PCNC se inició con la detección de la fenilcetonuria (PKU) y en el año 1982 se amplió con la detección del hipotiroidismo congénito. Hacia el año 1990 la cobertura territorial llegó casi al 100% de todos los recién nacidos en Cataluña. En 1999 se amplió el PCNC con la incorporación de la fibrosis quística y tras catorce años, en 2013, se realizó la ampliación más numerosa hasta ahora, con la incorporación de la detección de 19 enfermedades metabólicas hereditarias. En el año 2015 comenzó la detección de la enfermedad de células falciformes y en el 2017 la detección de la inmunodeficiencia combinada grave. Actualmente, el PCNC incluye la detección de 24 enfermedades. Desde su inicio en el año 1969, se han cribado 2.787.807 recién nacidos, de los cuales 1.724 han sido diagnosticados de alguna de las 24 enfermedades que componen nuestro panel principal y 252 por diagnóstico diferencial de las primeras. En total la prevalencia global es de 1:1.617 RN afectos de alguna de las enfermedades incluidas en el PCNC y de 1:1.140 RN si se incluyen los hallazgos incidentales encontrados


The Catalonian Newborn Screening Program (CNSP) began in 1969, in Barcelona. It was promoted by Dr. Juan Sabater Tobella and supported by Barcelona Provincial Council and Juan March Foundation. That is how the Institute of Clinical Biochemistry was born, whose aims were diagnosis, research and teaching, along with the spirit of contributing to the prevention of mental retardation. The CNSP began with the detection of phenylketonuria (PKU), and, in 1982, the Program was expanded with the inclusion of congenital hypothyroidism detection. Towards 1990, the Program covered almost 100% of all newborns (NB) in Catalonia. In 1999, the CNSP was expanded with the incorporation of cystic fibrosis. It took fourteen years, until 2013, to make the largest expansion so far, with the incorporation of 19 metabolic diseases to the screening panel. The detection of sickle cell disease began in 2015 and in 2017 the detection of severe combined immunodeficiency was included. Currently, the CNSP includes 24 diseases in its main panel. Since 1969, 2,787,807 NBs have been screened, of whom 1,724 have been diagnosed with any of these diseases, and 252 of other disorders by differential diagnosis with those included in the main panel. The global prevalence is 1: 1,617 NBs affected by any of the diseases included in the CNSP and 1: 1,140 NBs if incidental findings diagnosed through the CNSP are included


Subject(s)
Humans , Infant, Newborn , History, 15th Century , History, 16th Century , Neonatal Screening/history , Neonatal Screening/methods , Neonatal Screening/organization & administration , Spain
11.
Rev. cuba. anestesiol. reanim ; 18(3): e524, sept.-dic. 2019. tab, graf
Article in Spanish | CUMED, LILACS | ID: biblio-1093119

ABSTRACT

Introducción: El dolor posoperatorio constituye la principal causa de dolor agudo en el mundo. Brindar analgesia adecuada en el posquirúrgico garantiza la disminución de la estadía hospitalaria y tiene un impacto positivo en el resultado final de las intervenciones. Objetivo: Evaluar la efectividad de la analgesia posoperatoria con bupivacaína más morfina intratecal en la cirugía de próstata. Métodos: Se realizó una investigación cuasiexperimental, entre enero de 2015 y enero de 2018. La muestra quedó conformada de manera no probabilística por los pacientes que dieron su consentimiento informado y reunieron criterios para entrar en el estudio. Quedaron distribuidos de manera aleatoria en dos grupos denominados bupivacaína (B) y morfina-bupivacaína (MB). Para recolectar la información se emplearon las historias clínicas anestésicas y un formulario elaborado al efecto. Los resultados se mostraron en tablas y gráficos, se expresaron en frecuencias absolutas y en porcientos, se determinaron algunas medidas descriptivas de interés que mostraron el comportamiento de las variables que lo requirieron. Resultados: El resultado más relevante fue el efecto analgésico muy significativo en el grupo MB en las primeras 24 h del posoperatorio. La reacción adversa más frecuente fue el prurito y solo se presentó en el grupo que recibió morfina. Conclusiones: La anestesia espinal con morfina y bupivacaína es efectiva y segura, proporcionando mejor analgesia en el posoperatorio inmediato cuando se compara con bupivacaína sola(AU)


Introduction: Postoperative pain is the main cause of acute pain worldwide. Providing suitable analgesia in the postoperative period guarantees the reduction of hospital stay and has a positive impact on the final outcome of the interventions. Objective: To evaluate the effectiveness of postoperative analgesia with intrathecal administration of bupivacaine plus morphine in prostate surgery. Methods: A quasiexperimental research was carried out between January 2015 and January 2018. The sample was nonprobabilistic and made up by the patients who gave their informed consent and met criteria to enter the study. They were randomly distributed into two groups called bupivacaine (B) and morphine-bupivacaine (MB). To collect the information, the anesthetic medical records and a form prepared for this purpose were used. The results were shown in tables and graphs, expressed in absolute frequencies and percentages, some descriptive measures of interest were determined which showed the behavior of the variables that required it. Results: The most relevant result was the very significant analgesic effect in the MB group in the first 24 hours after surgery. The most frequent adverse reaction was pruritus and only occurred in the group that received morphine. Conclusions: Spinal anesthesia with morphine and bupivacaine is effective and safe, providing better analgesia in the immediate postoperative period when compared with bupivacaine alone(AU)


Subject(s)
Humans , Male , Pain, Postoperative/prevention & control , Pruritus/complications , Bupivacaine/therapeutic use , Anesthesia, Spinal/methods
12.
Rev. cuba. anestesiol. reanim ; 17(1): 1-9, ene.-abr. 2018. ilus, tab
Article in Spanish | LILACS, CUMED | ID: biblio-991014

ABSTRACT

Introducción: El dolor posoperatorio constituye la principal causa de dolor agudo en el mundo. Brindar analgesia adecuada en el posquirúrgico garantiza la disminución del tiempo de estancia hospitalaria y tiene un impacto positivo en el resultado final de los pacientes. Objetivo: Evaluar la calidad de la analgesia posoperatoria con bupivacaína más morfina intratecal en la cirugía electiva de próstata, así como la incidencia de efectos adversos. Métodos: Se realizó una investigación cuasiexperimental, entre enero de 2014 y julio de 2017. La muestra quedó conformada de manera no probabilística por los pacientes que dieron su consentimiento informado y reunieron criterios para entrar en el estudio. Quedaron distribuidos de manera aleatoria en dos grupos denominados bupivacaína (B) y morfina-bupivacaína (MB). Para recolectar la información se emplearon las historias clínicas anestésicas y un formulario elaborado al efecto. Los datos se mostraron en tablas y gráficos, los resultados se expresaron numéricamente y en porcientos, se determinaron algunas medidas descriptivas de interés que mostraron el comportamiento de las variables que lo requirieron. Resultados: El resultado más relevante fue el efecto analgésico muy significativo en el grupo MB en las primeras 24 h del posoperatorio. La reacción adversa más frecuente fue el prurito y solo se presentó en el grupo que recibió morfina. Conclusiones: La anestesia espinal con morfina y bupivacaína es efectiva y segura, proporcionando mejor analgesia en el posoperatorio inmediato cuando se compara con bupivacaína sola(AU)


Introduction: Postoperative pain is the main cause of acute pain worldwide. Providing adequate analgesia postoperatively guarantees hospital stay reduction and positively affects patient outcome. Objective: To evaluate the quality of postoperative analgesia with bupivacaine plus intrathecal morphine in elective prostate surgery, as well as the incidence of adverse effects. Methods: A quasiexperimental research was carried out between January 2014 and July 2017. The sample was chosen in a non-probabilistic way and made up by the patients who gave their informed consent and met the inclusion criteria to enter the study. They were randomly distributed into two groups identified as bupivacaine (B) and morphine-bupivacaine (MB). To collect the information, the anesthetic medical records were used, together with a form prepared for such purpose. The data were shown in charts and graphs, the results were expressed numerically and in percentages, some descriptive measures of interest were determined that showed the behavior of the variables that required it. Results: The most relevant outcome was the very significant analgesic effect in the MB group in the first 24 hours after surgery. The most common adverse reaction was pruritus and only occurred in the group that received morphine. Conclusions: Spinal anesthesia with morphine and bupivacaine is effective and safe because it provides better analgesia in the immediate postoperative period in comparison to bupivacaine alone(AU)


Subject(s)
Humans , Male , Pain, Postoperative/drug therapy , Bupivacaine/therapeutic use , Analgesics, Opioid/therapeutic use , Morphine/therapeutic use , Prostatectomy/methods , Prospective Studies , Longitudinal Studies , Long Term Adverse Effects/epidemiology
13.
Respir Med ; 131: 114-117, 2017 10.
Article in English | MEDLINE | ID: mdl-28947017

ABSTRACT

BACKGROUND: Alpha-1-antitrypsin (AAT) deficiency is a genetic condition that arises from mutations in the SERPINA1 gene and predisposes to develop pulmonary emphysema and, less frequently, liver disease. Occasionally, new defective SERPINA1 alleles are detected as an outcome of targeted-screening programs or case-findings. METHODS: This study began with a female patient showing bronchial hyperreactivity. Serum level and phenotype for AAT was analysed by immunonephelometry and isoelectric focusing electrophoresis. The SERPINA1 gene of the proband was genotyped by PCR amplification and DNA sequencing. Analysis of AAT deficiency was extended to the proband's family. RESULTS: An abnormal AAT variant that migrated to a more cathodal position than PiZ AAT was detected in the proband's serum. Genetic analysis demonstrated that proband is heterozygous for a new defective SERPINA1 allele (PI*Zla palma) characterized by the c.321C > A (p.Asn83Lys) mutation in the M1Val213 background. This mutation abolishes the N-glycosylation site in position 83 of the mature AAT. Eight relatives of the proband are carriers of the PI*Zla palma allele and four of them have shown symptoms of bronchial asthma or bronchial hyperreactivity. The mean α1AT level in the serum of PI*MZla palma individuals was 87.1 mg/dl. CONCLUSION: The reduction in circulating AAT levels associated to the PI*Zla palma allele was similar to that of PI*Z allele, representing a risk of impairment in lung function.


Subject(s)
Asthma/genetics , Bronchial Hyperreactivity/genetics , Glycosylation , alpha 1-Antitrypsin Deficiency/genetics , alpha 1-Antitrypsin/genetics , Alleles , Female , Humans , Isoelectric Focusing , Male , Middle Aged , Mutation , Nephelometry and Turbidimetry , Pedigree , Spain
16.
Am J Clin Nutr ; 81(3): 692-701, 2005 Mar.
Article in English | MEDLINE | ID: mdl-15755841

ABSTRACT

BACKGROUND: In rats, 30-70% of dietary fatty acids (FAs) are absorbed through the portal vein. Whether this occurs in humans is unknown, but it may occur in persons with cirrhosis, who show a blunted chylomicronemic response to dietary fat without significant steatorrhea. OBJECTIVE: The objective was to investigate whether portal FA absorption occurs in humans with cirrhosis. DESIGN: Six control subjects and 10 patients with (n = 5) and without (n = 5) cirrhotic ascites were fed [1-(13)C]palmitic and oleic acids in a test meal. Samples were drawn before and 30, 60, 90, 120, 240, 360, 480, and 720 min afterward for plasma [1-(13)C]-labeled FAs and breath (13)CO(2) assay. Fecal [1-(13)C]-labeled FAs were also measured. RESULTS: [1-(13)C]-Labeled FAs increased in chylomicrons in all groups, but less in ascitic cirrhotic patients, because their median area under the curve from 120 to 720 min was significantly lower than in the control subjects for labeled palmitate [520 (interquartile range: 192-1137) compared with 2862 (2674-4175) micromol . min/L] and oleate [829 (781-1263) compared with 3119 (2939-4986) micromol . min/L]. [1-(13)C]-Labeled FA enrichment of VLDL was also lower in cirrhotic patients. [1-(13)C]-Labeled FA in free FAs peaked earlier in ascitic than in nonascitic patients and control subjects, mainly for [1-(13)C]oleate, and the median area under the curve from 0 to 120 min was significantly higher in ascitic patients than in control subjects [301 (255-400) compared with 48 (34-185) micromol . min/L]. Fecal excretion of [1-(13)C]-labeled FA was negligible and not significantly different between groups. CONCLUSIONS: The low [1-(13)C]-labeled FA concentrations in chylomicrons and VLDL, without increased fecal losses, confirm previous data in cirrhotic patients with the use of an unlabeled fat load. The earlier [1-(13)C]-labeled FA appearance in free FAs supports the portal absorption of dietary fat in patients with advanced cirrhosis with spontaneous portal-systemic shunting.


Subject(s)
Ascites/metabolism , Dietary Fats/pharmacokinetics , Liver Cirrhosis/metabolism , Oleic Acid/pharmacokinetics , Palmitic Acid/pharmacokinetics , Aged , Area Under Curve , Ascites/etiology , Breath Tests , Carbon Isotopes , Case-Control Studies , Chylomicrons/chemistry , Feces/chemistry , Female , Humans , Intestinal Absorption , Liver Cirrhosis/complications , Male , Middle Aged , Portal Vein/metabolism
17.
Clin Chem ; 48(6 Pt 1): 906-12, 2002 Jun.
Article in English | MEDLINE | ID: mdl-12029007

ABSTRACT

BACKGROUND: Gas chromatographic-mass spectrometric (GC/MS) tracking of stable-isotope-labeled substrates is useful in metabolic studies. However, GC/MS analysis of long-chain fatty acid methyl esters yields results that mostly depend on their concentration in the system. We describe a protocol aimed to obviate this and other drawbacks in plasma [1-(13)C]palmitic and [1-(13)C]oleic acid measurements. METHODS: Lipoproteins were separated by sequential ultracentrifugation. Free or esterified heptadecanoic acid was used as internal standard. Fatty acids were derivatized to trimethylsilyl (TMS) esters. GC separation was in isothermal mode at 210 degrees C for 27 min. For both TMS-palmitate and TMS-oleate, M and [M + 1] signals were simultaneously acquired with a dual acquisition program in single-ion monitoring mode. Calibration mixtures containing increasing amounts of labeled fatty acids were prepared gravimetrically to construct calibration curves for isotopic enrichment. Likewise, five calibration curves (for increasing concentrations) were constructed for each fatty acid; this allowed selection of the most appropriate curve for the concentration in a plasma sample. RESULTS: Oleic acid-TMS ester was clearly separated from that of its stereoisomer, elaidic acid. Within a 10-fold concentration range, the isotopic ratio was independent on the amount of the analyte in the sample, with a maximum uncertainty of 0.34% in terms of molar percent excess. In addition, the within- and between-day imprecision (CV) of the method was <1%. CONCLUSION: Results obtained with this method are independent of concentration and sufficiently precise for tracking 1-(13)C-labeled palmitic and oleic acids in biological samples


Subject(s)
Oleic Acid/blood , Palmitic Acid/blood , Calibration , Carbon Isotopes , Gas Chromatography-Mass Spectrometry , Humans , Indicators and Reagents , Oleic Acid/chemistry , Palmitic Acid/chemistry , Sensitivity and Specificity , Trimethylsilyl Compounds , Ultracentrifugation
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