A comprehensive evaluation of omega-3 fatty acid supplementation in cystic fibrosis patients using lipidomics.

The evaluation of the benefits of omega-3 fatty acid supplementation in humans requires the identification and characterization of suitable biomarkers of its incorporation in the body. The reference method for the evaluation of omega-3, gas chromatography, is difficult to apply in clinical practice because of its low throughput and does not provide information about the incorporation of specific fatty acids in lipid species and the potential effects of supplementation on lipid classes. We used a quantitative lipidomic approach to follow the incorporation of omega-3 fatty acids into plasma lipids in cystic fibrosis patients (n=50) from a randomized controlled clinical trial after the supplementation of seaweed oil enriched with docosahexaenoic acid (DHA). Lipidomic analysis accurately showed the distribution of fatty acids in different lipid classes after omega-3 supplementation, and the performance in determining the compliance to supplementation was similar to that of gas chromatography coupled to mass spectrometry. Twelve months after fatty acid supplementation, DHA was predominantly incorporated into highly unsaturated cholesteryl esters (110.9±16.2 vs. 278.6±32.6 µM, mean±S.E.M.) and phosphatidylcholine (142.4±11.9 vs. 272.9±21.4 µM) and, to a lesser extent, into phosphatidylethanolamine (9.4±0.8 vs. 15.5±1.5 µM) and triglycerides (0.4±0.04 vs. 1.1±0.12 µM). In addition, a technique was developed for the fast measurement of the DHA/arachidonic acid ratio to simplify the follow-up of nutritional intervention with DHA-enriched foods. We conclude that lipidomics is a suitable approach for monitoring the incorporation of omega-3 fatty acids in nutritional studies.

Association of the relative change in weight and body mass index with lung function in teenagers and adults with cystic fibrosis: Influence of gender and diabetes.

BACKGROUND: Nutritional status is a prognostic factor in cystic fibrosis. Prevention of nutritional impairment and weigh loss are major clinical objectives because they are associated with worsening of lung function and increased mortality. OBJECTIVE: To identify a potential relationship of clinical nutrition parameters, and their relative changes, with lung function (FEV1%) in a cohort of adolescent and adult patients with CF. METHODS: A retrospective analysis of 64 patients older than 14years. Weight, height, BMI, and lung function data were collected at a period of disease stability, both in the year of the first abnormal oral glucose tolerance test (OGTT) and in the previous year. Relative changes in weight and BMI, and their relationship with FEV1%, were determined by linear regression and ANOVA tests; influence of gender and diabetes was also assessed. RESULTS: Mean age of the series (28 females and 36 males) was 26.8years. Normal glucose tolerance (NGT) was found in 26.7%, while 18.3% had diabetes without impaired fasting glucose (CFRD without FPG). Mean BMI was 20.32, with a mean weight of 53.53kg; 32.8% had BMI<18.5, and only 4.7% were overweight. Overall, a positive relative change in weight (≥6%) was associated with an increase in FEV1% (9.31%), as compared to those with a greater weight loss (at least 2%), who had a 12.09% fall in FEV1. Patients with CFRD without FPG had poorer lung function if they had a negative relative change in weight by at least 2% as compared to NGT. CONCLUSIONS: In patients with CF, a relative weight gain is positively associated to FEV1%, while a relative weight loss of at least 2% has a significant negative impact on lung function.

Insulin resistance, ß-cell dysfunction and differences in curves of plasma glucose and insulin in the intermediate points of the standard glucose tolerance test in adults with cystic fibrosis.

BACKGROUND: diabetes has become a co-morbidity with a negative impact on nutritional status, lung function and survival in cystic fibrosis. OBJECTIVE: To identify any changes in intermediate points after a 2-hour oral glucose tolerance test (OGTT), pancreatic ß-cell dysfunction, and insulin resistance in cystic fibrosis-related diabetes. METHODS: It was carried out a retrospective analysis in a cohort of 64 patients affected of cystic fibrosis, older than 14 years, using the first pathological OGTT. Peripheral insulin resistance was measured using the homeostasis model assessment for insulin resistance (HOMA- IR), and pancreatic ß-cell function was calculated according to Wareham. Time to maximum plasma insulin and glucose levels and area under the curve (AUC0-120) were also measured. RESULTS: Twenty-eight women and 36 men with a mean age of 26.8 years were enrolled, of whom 26.7% had normal glucose tolerance (NGT), 18.3% cystic fibrosis-related diabetes without fasting hyperglycemia (CFRD w/o FPG), 10% indeterminate (INDET), and 45% impaired glucose tolerance (IGT). HOMA-IR values were not significantly different between the diagnostic categories. Patients with any pathological change had worse ß cell function, with a significant delay in insulin secretion, although there were no differences in total insulin production (AUC0-120). Time to maximum glucose levels was significantly shorter in NGT patients as compared to other categories, with glucose AUC0-120 being higher in the different diagnostic categories as compared to NGT. CONCLUSIONS: In over half the cases, peak blood glucose levels during a standard OGTT are reached in the intermediate time points, rather than at the usual time of 120minutes. Patients with cystic fibrosis and impaired glucose metabolism have a delayed insulin secretion during the standard OGTT due to loss of first-phase insulin secretion, with no differences in total insulin production. Absence of significant changes in HOMA-IR suggests that ß-cell dysfunction is the main pathogenetic mechanism.

[Tolerance of two inhaled hypertonic saline solutions in patients with cystic fibrosis]. / Tolerabilidad de la inhalación de dos soluciones salinas hipertónicas en pacientes con fibrosis quística.

BACKGROUND AND OBJECTIVE: The aim of our study was to evaluate the tolerance of two inhaled hypertonic saline solutions (HS) in patients with cystic fibrosis. PATIENTS AND METHOD: Eighty one cystic fibrosis (CF) patients (44 males; mean age 23.63 years) inhaled 5 ml of 7% inhaled HS solution and, in those patients who did not tolerate HS, we evaluated the tolerance of a 7% HS (at dose of 5 ml) added to 0.1% hyaluronic acid at least twenty-four hours later. RESULTS: Twenty one (26%) patients did not tolerate the HS solution immediately after its inhalation. Cough was the most common symptom. Patients over 18 years of age showed worse tolerance to HS than patients younger than 18 years of age. Those patients that did not tolerate HS had a worse lung function that the ones that showed good tolerance. Eighty-one percent of patients who did not tolerate the HS alone tolerated well the HS with hyaluronic acid. CONCLUSIONS: CF patients cannot tolerate inhaled HS immediately after nebulisation. Patients over 18 years and those with worse lung function tolerate HS worst. Hyaluronate acid added to 7% HS solution improves the tolerability.