Abnormal unsaturated fatty acid metabolism in cystic fibrosis: biochemical mechanisms and clinical implications

Dysregulation of the Arachidonic Acid Pathway in Cystic Fibrosis: Implications for Chronic Inflammation and Disease Progression

Cystic fibrosis (CF) is the most common fatal genetic disease among Caucasian people, with over 2000 mutations in the CFTR gene. Although highly effective modulators have been developed to rescue the mutant CFTR protein, unresolved inflammation and persistent infections still threaten the lives of patients. While the central role of arachidonic acid (AA) and its metabolites in the inflammatory response is widely recognized, less is known about their impact on immunomodulation and metabolic implications in CF. To this end, here we provided a comprehensive analysis of the AA metabolism in CF. In this context, CFTR dysfunction appeared to complexly disrupt normal lipid processing, worsening the chronic airway inflammation, and compromising the immune responses to bacterial infections. As such, potential strategies targeting AA and its inflammatory mediators are being investigated as a promising approach to balance the inflammatory response while mitigating disease progression. Thus, a deeper understanding of the AA pathway dysfunction in CF may open innovative avenues for designing more effective therapeutic interventions.

Cutaneous manifestations of cystic fibrosis

Cystic fibrosis (CF) is caused by a mutation in the Cystic fibrosis transmembrane conductance regulator (CFTR) gene, and features recurrent sinus and pulmonary infections, steatorrhea, and malnutrition. CF is associated with diverse cutaneous manifestations, including transient reactive papulotranslucent acrokeratoderma of the palms, nutrient deficiency dermatoses, and vasculitis. Rarely these are presenting symptoms of CF, prior to pulmonary or gastrointestinal sequelae. Cutaneous drug eruptions are also highly common in patients with CF (PwCF) given frequent antibiotic exposure. Finally, CFTR modulating therapy, which has revolutionized CF management, is associated with cutaneous side effects ranging from acute urticaria to toxic epidermal necrolysis. Recognition of dermatologic clinical manifestations of CF is important to appropriately care for PwCF. Dermatologists may play a significant role in the diagnosis and management of CF and associated skin complications.

The olfactory bulb: A neuroendocrine spotlight on feeding and metabolism

Olfaction is the most ancient sense and is needed for food-seeking, danger protection, mating and survival. It is often the first sensory modality to perceive changes in the external environment, before sight, taste or sound. Odour molecules activate olfactory sensory neurons that reside on the olfactory epithelium in the nasal cavity, which transmits this odour-specific information to the olfactory bulb (OB), where it is relayed to higher brain regions involved in olfactory perception and behaviour. Besides odour processing, recent studies suggest that the OB extends its function into the regulation of food intake and energy balance. Furthermore, numerous hormone receptors associated with appetite and metabolism are expressed within the OB, suggesting a neuroendocrine role outside the hypothalamus. Olfactory cues are important to promote food preparatory behaviours and consumption, such as enhancing appetite and salivation. In addition, altered metabolism or energy state (fasting, satiety and overnutrition) can change olfactory processing and perception. Similarly, various animal models and human pathologies indicate a strong link between olfactory impairment and metabolic dysfunction. Therefore, understanding the nature of this reciprocal relationship is critical to understand how olfactory or metabolic disorders arise. This present review elaborates on the connection between olfaction, feeding behaviour and metabolism and will shed light on the neuroendocrine role of the OB as an interface between the external and internal environments. Elucidating the specific mechanisms by which olfactory signals are integrated and translated into metabolic responses holds promise for the development of targeted therapeutic strategies and interventions aimed at modulating appetite and promoting metabolic health.

Elevated Prostaglandin E2 Synthesis Is Associated with Clinical and Radiological Disease Severity in Cystic Fibrosis

Background: Previous studies found high but very variable levels of tetranor-PGEM and PGDM (urine metabolites of prostaglandin (PG) E2 and PGD2, respectively) in persons with cystic fibrosis (pwCF). This study aims to assess the role of cyclooxygenase COX-1 and COX-2 genetic polymorphisms in PG production and of PG metabolites as potential markers of symptoms' severity and imaging findings. Methods: A total of 30 healthy subjects and 103 pwCF were included in this study. Clinical and radiological CF severity was evaluated using clinical scoring methods and chest computed tomography (CT), respectively. Urine metabolites were measured using liquid chromatography/tandem mass spectrometry. Variants in the COX-1 gene (PTGS1 639 C>A, PTGS1 762+14delA and COX-2 gene: PTGS2-899G>C (-765G>C) and PTGS2 (8473T>C) were also analyzed. Results: PGE-M and PGD-M urine concentrations were significantly higher in pwCF than in controls. There were also statistically significant differences between clinically mild and moderate disease and severe disease. Patients with bronchiectasis and/or air trapping had higher PGE-M levels than patients without these complications. The four polymorphisms did not associate with clinical severity, air trapping, bronchiectasis, or urinary PG levels. Conclusions: These results suggest that urinary PG level testing can be used as a biomarker of CF severity. COX genetic polymorphisms are not involved in the variability of PG production.

Impact of 1-Year Supplementation with High-Rich Docosahexaenoic Acid (DHA) on Clinical Variables and Inflammatory Biomarkers in Pediatric Cystic Fibrosis: A Randomized Double-Blind Controlled Trial

A randomized, double-blind, and placebo-controlled study was conducted to assess the effect of dietary supplementation with high-rich docosahexaenoic acid (DHA) (Tridocosahexanoin-AOX® 70%) at 50 mg/kg/day in pediatric patients with cystic fibrosis (CF) as compared with placebo. The duration of supplementation was 12 months. A total of 22 patients were included, with 11 in the DHA group and 11 in the placebo group. The mean age was 11.7 years. The outcome variables were pulmonary function, exacerbations, sputum cellularity, inflammatory biomarkers in sputum and peripheral blood, and anthropometric variables. In the DHA group, there was a significant increase in FVC (p = 0.004) and FVE1 expressed in liters (p = 0.044) as compared with placebo, and a lower median number of exacerbations (1 vs. 2). Differences in sputum cellularity (predominantly neutrophilic), neutrophilic elastase, and sputum and serum concentrations of resolvin D1 (RvD1), interleukin (IL)-8 (IL-8), and tumor necrosis factor alpha (TNF-α) between the study groups were not found. Significant increases in weight and height were also observed among DHA-supplemented patients. The administration of the study product was safe and well tolerated. In summary, the use of a highly concentrated DHA supplement for 1 year as compared with placebo improved pulmonary function and reduced exacerbations in pediatric CF.

ACOX1 deficiency-induced lipid metabolic disorder facilitates chronic interstitial fibrosis development in renal allografts

Chronic interstitial fibrosis presents a significant challenge to the long-term survival of transplanted kidneys. Our research has shown that reduced expression of acyl-coenzyme A oxidase 1 (ACOX1), which is the rate-limiting enzyme in the peroxisomal fatty acid β-oxidation pathway, contributes to the development of fibrosis in renal allografts. ACOX1 deficiency leads to lipid accumulation and excessive oxidation of polyunsaturated fatty acids (PUFAs), which mediate epithelial-mesenchymal transition (EMT) and extracellular matrix (ECM) reorganization respectively, thus causing fibrosis in renal allografts. Furthermore, activation of Toll-like receptor 4 (TLR4)-nuclear factor kappa-B (NF-κB) signaling induced ACOX1 downregulation in a DNA methyltransferase 1 (DNMT1)-dependent manner. Overconsumption of PUFA resulted in endoplasmic reticulum (ER) stress, which played a vital role in facilitating ECM reorganization. Supplementation with PUFAs contributed to delayed fibrosis in a rat model of renal transplantation. The study provides a novel therapeutic approach that can delay chronic interstitial fibrosis in renal allografts by targeting the disorder of lipid metabolism.

Changes of Erythrocyte Fatty Acids after Supplementation with Highly Concentrated Docosahexaenoic Acid (DHA) in Pediatric Cystic Fibrosis: A Randomized Double-Blind Controlled Trial

We characterized the fatty acid profiles in the erythrocyte membrane of pediatric patients with cystic fibrosis (CF) receiving highly concentrated docosahexaenoic acid (DHA) supplementation (Tridocosahexanoin-AOX^® 70%) at 50 mg/kg/day (n = 11) or matching placebo (n = 11) for 12 months. The mean age was 11.7 years. The DHA group showed a statistically significant improvement in n-3 polyunsaturated fatty acids (PUFAs), which was observed as early as 6 months and further increased at 12 months. Among the n-3 PUFAs, there was a significant increase in DHA and eicosapentaenoic acid (EPA). Additionally, a statistically significant decrease in n-6 PUFAs was found, primarily due to a decrease in arachidonic acid (AA) levels and elongase 5 activity. However, we did not observe any changes in linoleic acid levels. The long-term administration of DHA over one year was safe and well tolerated. In summary, the administration of a high-rich DHA supplement at a dose of 50 mg/kg/day for one year can correct erythrocyte AA/DHA imbalance and reduce fatty acid inflammatory markers. However, it is important to note that essential fatty acid alterations cannot be fully normalized with this treatment. These data provide timely information of essential fatty acid profile for future comparative research.

Changes in Essential Fatty Acids and Ileal Genes Associated with Metabolizing Enzymes and Fatty Acid Transporters in Rodent Models of Cystic Fibrosis

Cystic fibrosis (CF), the result of mutations in the CF transmembrane conductance regulator (CFTR), causes essential fatty acid deficiency. The aim of this study was to characterize fatty acid handling in two rodent models of CF; one strain which harbors the loss of phenylalanine at position 508 (Phe508del) in CFTR and the other lacks functional CFTR (510X). Fatty acid concentrations were determined using gas chromatography in serum from Phe508del and 510X rats. The relative expression of genes responsible for fatty acid transport and metabolism were quantified using real-time PCR. Ileal tissue morphology was assessed histologically. There was an age-dependent decrease in eicosapentaenoic acid and the linoleic acid:α-linolenic acid ratio, a genotype-dependent decrease in docosapentaenoic acid (n-3) and an increase in the arachidonic acid:docosahexaenoic acid ratio in Phe508del rat serum, which was not observed in 510X rats. In the ileum, Cftr mRNA was increased in Phe508del rats but decreased in 510X rats. Further, Elvol2, Slc27a1, Slc27a2 and Got2 mRNA were increased in Phe508del rats only. As assessed by Sirius Red staining, collagen was increased in Phe508del and 510X ileum. Thus, CF rat models exhibit alterations in the concentration of circulating fatty acids, which may be due to altered transport and metabolism, in addition to fibrosis and microscopic structural changes in the ileum.

Nutrition in Cystic Fibrosis—Some Notes on the Fat Recommendations

Nutrition is important in cystic fibrosis (CF) because the disease is associated with a higher energy consumption, special nutritional deficiencies, and malabsorption mainly related to pancreatic insufficiency. The clinical course with deterioration of lung function has been shown to relate to nutrition. Despite general recommendation of high energy intake, the clinical deterioration is difficult to restrain suggesting that special needs have not been identified and specified. It is well-known that the CF phenotype is associated with lipid abnormalities, especially in the essential or conditionally essential fatty acids. This review will concentrate on the qualitative aspects of fat metabolism, which has mainly been neglected in dietary fat recommendations focusing on fat quantity. For more than 60 years it has been known and confirmed that the patients have a deficiency of linoleic acid, an n-6 essential fatty acid of importance for membrane structure and function. The ratio between arachidonic acid and docosahexaenoic acid, conditionally essential fatty acids of the n-6 and n-3 series, respectively, is often increased. The recently discovered relations between the CFTR modulators and lipid metabolism raise new interests in this field and together with new technology provide possibilities to specify further specify personalized therapy.

Role for animal models in understanding essential fatty acid deficiency in cystic fibrosis

Essential fatty acid deficiency has been observed in most patients with Cystic Fibrosis (CF); however, pancreatic supplementation does not restore the deficiency, suggesting a different pathology independent of the pancreas. At this time, the underlying pathological mechanisms are largely unknown. Essential fatty acids are obtained from the diet and processed by organs including the liver and intestine, two organs significantly impacted by mutations in the cystic fibrosis transmembrane conductance regulator gene (Cftr). There are several CF animal models in a variety of species that have been developed to investigate molecular mechanisms associated with the CF phenotype. Specifically, global and systemic mutations in Cftr which mimic genotypic changes identified in CF patients have been generated in mice, rats, sheep, pigs and ferrets. These mutations produce CFTR proteins with a gating defect, trafficking defect, or an absent or inactive CFTR channel. Essential fatty acids are critical to CFTR function, with a bidirectional relationship between CFTR and essential fatty acids proposed. Currently, there are limited analyses on the essential fatty acid status in most of these animal models. Of interest, in the mouse model, essential fatty acid status is dependent on the genotype and resultant phenotype of the mouse. Future investigations should identify an optimal animal model that has most of the phenotypic changes associated with CF including the essential fatty acid deficiencies, which can be used in the development of therapeutics.

CFTR Protein: Not Just a Chloride Channel?

Cystic fibrosis (CF) is a recessive genetic disease caused by mutations in a gene encoding a protein called Cystic Fibrosis Transmembrane Conductance Regulator (CFTR). The CFTR protein is known to acts as a chloride (Cl-) channel expressed in the exocrine glands of several body systems where it also regulates other ion channels, including the epithelial sodium (Na+) channel (ENaC) that plays a key role in salt absorption. This function is crucial to the osmotic balance of the mucus and its viscosity. However, the pathophysiology of CF is more challenging than a mere dysregulation of epithelial ion transport, mainly resulting in impaired mucociliary clearance (MCC) with consecutive bronchiectasis and in exocrine pancreatic insufficiency. This review shows that the CFTR protein is not just a chloride channel. For a long time, research in CF has focused on abnormal Cl- and Na+ transport. Yet, the CFTR protein also regulates numerous other pathways, such as the transport of HCO3-, glutathione and thiocyanate, immune cells, and the metabolism of lipids. It influences the pH homeostasis of airway surface liquid and thus the MCC as well as innate immunity leading to chronic infection and inflammation, all of which are considered as key pathophysiological characteristics of CF.

Dietary phenotype and advanced glycation end-products predict WTC-obstructive airways disease: a longitudinal observational study

BACKGROUND

Diet is a modifier of metabolic syndrome which in turn is associated with World Trade Center obstructive airways disease (WTC-OAD). We have designed this study to (1) assess the dietary phenotype (food types, physical activity, and dietary habits) of the Fire Department of New York (FDNY) WTC-Health Program (WTC-HP) cohort and (2) quantify the association of dietary quality and its advanced glycation end product (AGE) content with the development of WTC-OAD.

METHODS

WTC-OAD, defined as developing WTC-Lung Injury (WTC-LI; FEV1 < LLN) and/or airway hyperreactivity (AHR; positive methacholine and/or positive bronchodilator response). Rapid Eating and Activity Assessment for Participants-Short Version (REAP-S) deployed on 3/1/2018 in the WTC-HP annual monitoring assessment. Clinical and REAP-S data of consented subjects was extracted (7/17/2019). Diet quality [low-(15-19), moderate-(20-29), and high-(30-39)] and AGE content per REAP-S questionnaire were assessed for association with WTC-OAD. Regression models adjusted for smoking, hyperglycemia, hypertension, age on 9/11, WTC-exposure, BMI, and job description.

RESULTS

N = 9508 completed the annual questionnaire, while N = 4015 completed REAP-S and had spirometry. WTC-OAD developed in N = 921, while N = 3094 never developed WTC-OAD. Low- and moderate-dietary quality, eating more (processed meats, fried foods, sugary drinks), fewer (vegetables, whole-grains),and having a diet abundant in AGEs were significantly associated with WTC-OAD. Smoking was not a significant risk factor of WTC-OAD.

CONCLUSIONS

REAP-S was successfully implemented in the FDNY WTC-HP monitoring questionnaire and produced valuable dietary phenotyping. Our observational study has identified low dietary quality and AGE abundant dietary habits as risk factors for pulmonary disease in the context of WTC-exposure. Dietary phenotyping, not only focuses our metabolomic/biomarker profiling but also further informs future dietary interventions that may positively impact particulate matter associated lung disease.

Cystic fibrosis: Physiopathology and the latest pharmacological treatments

Cystic fibrosis (CF) is a lethal autosomal recessive genetic disease, caused by a mutation in the cystic fibrosis transmembrane conductance regulator gene (CFTR), which primarily affects the lungs and digestive system. This gene encodes the CFTR protein, a distinctive membrane transporter of the ATP-binding cassette (ABC) superfamily. It functions as a chloride channel, allowing the balance and transport of chloride through the apical membrane of epithelial cells. Due to its ubiquitous location, mutations in the CFTR gene trigger multiple changes in ion transport and metabolic pathways, affecting various organs, as it will be herein explained. Pulmonary impairment is the most characteristic comorbidity of CF and respiratory failure is the main cause of death. This review presents the importance of an early diagnosis of CF to establish, as soon as possible, a primary therapy for symptomatic prevention and relief. It also mentions new therapeutic approaches that include CFTR modulators. They are correctors and/or potentiators of the deficient CFTR channel. In an attempt to overcome the disadvantages of CFTR modulators, the application of biotechnology techniques is addressed, such as gene therapy, gene editing, RNA therapy and therapeutic microRNAs. The potential of the intranasal administration route is another presented aspect.

Food Intake REstriction for Health OUtcome Support and Education (FIREHOUSE) Protocol: A Randomized Clinical Trial

Fire Department of New York (FDNY) rescue and recovery workers exposed to World Trade Center (WTC) particulates suffered loss of forced expiratory volume in 1 s (FEV1). Metabolic Syndrome increased the risk of developing WTC-lung injury (WTC-LI). We aim to attenuate the deleterious effects of WTC exposure through a dietary intervention targeting these clinically relevant disease modifiers. We hypothesize that a calorie-restricted Mediterranean dietary intervention will improve metabolic risk, subclinical indicators of cardiopulmonary disease, quality of life, and lung function in firefighters with WTC-LI. To assess our hypothesis, we developed the Food Intake REstriction for Health OUtcome Support and Education (FIREHOUSE), a randomized controlled clinical trial (RCT). Male firefighters with WTC-LI and a BMI > 27 kg/m2 will be included. We will randomize subjects (1:1) to either: (1) Low Calorie Mediterranean (LoCalMed)-an integrative multifactorial, technology-supported approach focused on behavioral modification, nutritional education that will include a self-monitored diet with feedback, physical activity recommendations, and social cognitive theory-based group counseling sessions; or (2) Usual Care. Outcomes include reduction in body mass index (BMI) (primary), improvement in FEV1, fractional exhaled nitric oxide, pulse wave velocity, lipid profiles, targeted metabolic/clinical biomarkers, and quality of life measures (secondary). By implementing a technology-supported LoCalMed diet our FIREHOUSE RCT may help further the treatment of WTC associated pulmonary disease.

Influence of lung transplantation on the essential fatty acid profile in cystic fibrosis

Lung transplantation is assumed to normalize essential fatty acid (EFA) profile in the plasma, described as abnormal in patients with cystic fibrosis (CF). This study sought to evaluate the EFA profile in both the plasma and erythrocyte membrane according to lung status by comparing CF patients with or without a lung transplant. A total of 50 homozygous F508del patients (33 CF patients [CF group] and 17 CF patients with a lung transplant [TX CF group]) were included. In comparison with the CF group, in the plasma, the levels of total n-3, α-linolenic, eicosapentaenoic, and docosahexaenoic acids were higher and the n-6/n-3 ratio was lower in the TX CF group. Yet, these differences were not observed in the erythrocyte membrane. This study supports that lung transplantation improves the EFA profile in the plasma but not in the erythrocyte membrane by means of the different mechanisms suggested in this article.

An Innovative Lipidomic Workflow to Investigate the Lipid Profile in a Cystic Fibrosis Cell Line

Altered lipid metabolism has been associated to cystic fibrosis disease, which is characterized by chronic lung inflammation and various organs dysfunction. Here, we present the validation of an untargeted lipidomics approach based on high-resolution mass spectrometry aimed at identifying those lipid species that unequivocally sign CF pathophysiology. Of n.13375 mass spectra recorded on cystic fibrosis bronchial epithelial airways epithelial cells IB3, n.7787 presented the MS/MS data, and, after software and manual validation, the final number of annotated lipids was restricted to n.1159. On these lipids, univariate and multivariate statistical approaches were employed in order to select relevant lipids for cellular phenotype discrimination between cystic fibrosis and HBE healthy cells. In cystic fibrosis IB3 cells, a pervasive alteration in the lipid metabolism revealed changes in the classes of ether-linked phospholipids, cholesterol esters, and glycosylated sphingolipids. Through functions association, it was evidenced that lipids variation involves the moiety implicated in membrane composition, endoplasmic reticulum, mitochondria compartments, and chemical and biophysical lipids properties. This study provides a new perspective in understanding the pathogenesis of cystic fibrosis and strengthens the need to use a validated mass spectrometry-based lipidomics approach for the discovery of potential biomarkers and perturbed metabolism.

Proof of concept for identifying cystic fibrosis from perspiration samples

The gold standard for cystic fibrosis (CF) diagnosis is the determination of chloride concentration in sweat. Current testing methodology takes up to 3 h to complete and has recognized shortcomings on its diagnostic accuracy. We present an alternative method for the identification of CF by combining desorption electrospray ionization mass spectrometry and a machine-learning algorithm based on gradient boosted decision trees to analyze perspiration samples. This process takes as little as 2 min, and we determined its accuracy to be 98 ± 2% by cross-validation on analyzing 277 perspiration samples. With the introduction of statistical bootstrap, our method can provide a confidence estimate of our prediction, which helps diagnosis decision-making. We also identified important peaks by the feature selection algorithm and assigned the chemical structure of the metabolites by high-resolution and/or tandem mass spectrometry. We inspected the correlation between mild and severe CFTR gene mutation types and lipid profiles, suggesting a possible way to realize personalized medicine with this noninvasive, fast, and accurate method.

Association between fat-soluble nutrient status and auditory and visual related potentials in newly diagnosed non-screened infants with cystic fibrosis: A case-control study

Nutritional deficiencies often precede the diagnosis of cystic fibrosis (CF) in infants, and occur at a stage where the rapidly developing brain is more vulnerable to insult. We aim to compare fat-soluble nutrient status of newly diagnosed non-screened infants with CF to that of healthy infants, and explore the association with neurodevelopment evaluated by electroencephalography (EEG). Our results show that CF infants had lower levels of all fat-soluble vitamins and docosahexaenoic acid (DHA) compared to controls. The auditory evoked potential responses were higher in CF compared to controls whereas the visual components did not differ between groups. DHA levels were correlated with auditory evoked potential responses. Although resting state frequency power was similar between groups, we observed a negative correlation between DHA levels and low frequencies. This study emphasizes the need for long-term neurodevelopmental follow-up of CF infants and pursuing intervention strategies in the future.

Validation of Predictive Metabolic Syndrome Biomarkers of World Trade Center Lung Injury: A 16-Year Longitudinal Study

BACKGROUND

Metabolic syndrome (MetSyn) predicted future development of World Trade Center lung injury (WTC-LI) in a subgroup of firefighters who never smoked and were male. An intracohort validation of MetSyn as a predictor of WTC-LI is examined in the cohort exposed to the World Trade Center (WTC) that has been followed longitudinally for 16 years.

METHODS

Results of pulmonary function tests (n = 98,221) in workers exposed to the WTC (n = 9,566) were evaluated. A baseline cohort of firefighters who had normal FEV1 before 9/11 and who had had serum drawn before site closure on July 24, 2002 (n = 7,487) was investigated. Case subjects with WTC-LI (n = 1,208) were identified if they had at least two measured instances of FEV1 less than the lower limit of normal (LLN). Cox proportional hazards modeled early MetSyn biomarker ability to predict development of FEV1 less than the LLN.

RESULTS

Case subjects were more likely to smoke, be highly exposed, and have MetSyn. There was a significant exposure dose response; the individuals most highly exposed had a 30.1% increased risk of developing WTC-LI, having MetSyn increased risk of developing WTC-LI by 55.7%, and smoking increased risk by 15.2%. There was significant interaction between smoking and exposure.

CONCLUSIONS

We validated the usefulness of MetSyn to predict future WTC-LI in a larger population of individuals who were exposed. MetSyn defined by dyslipidemia, insulin resistance, and cardiovascular disease suggests that systemic inflammation can contribute to future lung function loss.

Current and upcoming therapies to modulate skin scarring and fibrosis

Skin is the largest organ of the human body. Being the interface between the body and the outer environment, makes it susceptible to physical injury. To maintain life, nature has endowed skin with a fast healing response that invariably ends in the formation of scar at the wounded dermal area. In many cases, skin remodelling may be impaired, leading to local hypertrophic scars or keloids. One should also consider that the scarring process is part of the wound healing response, which always starts with inflammation. Thus, scarring can also be induced in the dermis, in the absence of an actual wound, during chronic inflammatory processes. Considering the significant portion of the population that is subject to abnormal scarring, this review critically discusses the state-of-the-art and upcoming therapies in skin scarring and fibrosis.

Receptor for advanced glycation end-products and environmental exposure related obstructive airways disease: a systematic review

Background

Our group has identified the receptor for advanced glycation end-products (RAGE) as a predictor of World Trade Center particulate matter associated lung injury. The aim of this systematic review is to assess the relationship between RAGE and obstructive airways disease secondary to environmental exposure.

Methods

A comprehensive search using PubMed and Embase was performed on January 5, 2018 utilising keywords focusing on environmental exposure, obstructive airways disease and RAGE and was registered with PROSPERO (CRD42018093834). We included original human research studies in English, focusing on pulmonary end-points associated with RAGE and environmental exposure.

Results

A total of 213 studies were identified by the initial search. After removing the duplicates and applying inclusion and exclusion criteria, we screened the titles and abstracts of 61 studies. Finally, 19 full-text articles were included. The exposures discussed in these articles include particulate matter (n=2) and cigarette smoke (n=17).

Conclusion

RAGE is a mediator of inflammation associated end-organ dysfunction such as obstructive airways disease. Soluble RAGE, a decoy receptor, may have a protective effect in some pulmonary processes. Overall, RAGE is biologically relevant in environmental exposure associated lung disease. Future investigations should focus on further understanding the role and therapeutic potential of RAGE in particulate matter exposure associated lung disease.

RAGE is biologically relevant in environmental exposure associated lung disease. Future investigations should focus on further understanding the role and therapeutic potential of RAGE in particulate matter exposure associated lung diseasehttp://ow.ly/gfZz30o7otU

Fatty acid profile in erythrocytes associated with serum cytokines in pediatric cystic fibrosis patients

ABSTRACT Objective To analyze erythrocyte fatty acid composition and its association with serum cytokine levels in pediatric cystic fibrosis patients. Methods A cross-sectional study was performed at a reference center in Rio de Janeiro, Brazil. We have included all pediatric patients aged 5-19 years with confirmed cystic fibrosis diagnosis. Erythrocyte fatty acid composition and serum cytokine (TNF-α, IL-1β, IL-6 and IL-8) and C-reactive protein levels were measured. The cut-off point to determine essential fatty acids deficiency was the linoleic acid concentration of <21%. Results Twenty-six children (<10 years old) and thirty-one adolescents were studied. Most patients were female and heterozygous for DF508 mutation and suffered from exocrine pancreatic insufficiency. Both children and adolescents had lower linoleic acid concentration (<21%). TNF-α was the only pro-inflammatory marker whose levels were increased; the increase was greater in children. An association between fatty acid composition in erythrocytes and cytokines IL-1β and IL-6 was observed (p<0.05). Conclusion The pediatric cystic fibrosis patients studied presented a deficiency of essential fatty acids, and an association between fatty acid profile in erythrocytes and serum pro-inflammatory cytokines was observed. These findings highlight the importance of this type of assessment that may open new possibilities for studying pathophysiology and treating cystic fibrosis patients, such as the dietary supplementation with n-3 fatty acids (eicosapentaenoic and docosahexaenoic acids). However, further longitudinal studies are needed for better clarification of the imbalance in lipid metabolism and inflammation in cystic fibrosis

Pseudomonas aeruginosa responds to exogenous polyunsaturated fatty acids (PUFAs) by modifying phospholipid composition, membrane permeability, and phenotypes associated with virulence

Background

Pseudomonas aeruginosa, a common opportunistic pathogen, is known to cause infections in a variety of compromised human tissues. An emerging mechanism for microbial survival is the incorporation of exogenous fatty acids to alter the cell’s membrane phospholipid profile. With these findings, we show that exogenous fatty acid exposure leads to changes in bacterial membrane phospholipid structure, membrane permeability, virulence phenotypes and consequent stress responses that may influence survival and persistence of Pseudomonas aeruginosa.

Results

Thin-layer chromatography and ultra performance liquid chromatography / ESI-mass spectrometry indicated alteration of bacterial phospholipid profiles following growth in the presence of polyunsaturated fatty acids (PUFAs) (ranging in carbon length and unsaturation). The exogenously supplied fatty acids were incorporated into the major bacterial phospholipids phosphatidylethanolamine and phosphatidylglycerol. The incorporation of fatty acids increased membrane permeability as judged by both accumulation and exclusion of ethidium bromide. Individual fatty acids were identified as modifying resistance to the cyclic peptide antibiotics polymyxin B and colistin, but not the beta-lactam imipenem. Biofilm formation was increased by several PUFAs and significant fluctuations in swimming motility were observed.

Conclusions

Our results emphasize the relevance and complexity of exogenous fatty acids in the membrane physiology and pathobiology of a medically important pathogen. P. aeruginosa exhibits versatility with regard to utilization of and response to exogenous fatty acids, perhaps revealing potential strategies for prevention and control of infection.

Electronic supplementary material

The online version of this article (10.1186/s12866-018-1259-8) contains supplementary material, which is available to authorized users.

Serum Phospholipid Fatty Acid Composition in Cystic Fibrosis Patients with and without Liver Cirrhosis

Background/Aims: Cystic fibrosis (CF) liver disease is the third most frequent cause of death in CF patients. Although it alters fatty acid (FA) metabolism, data concerning the profile of FA in CF patients with liver cirrhosis is lacking. This study aimed to assess the FA composition of serum phospholipids in CF patients with and without liver cirrhosis. Methods: The study comprised 25 CF patients with liver cirrhosis and 25 without it. We assessed Z-scores for body height and weight, lung function, exocrine pancreatic sufficiency and colonization with Pseudomonas aeruginosa. FAs' profile of serum glycerophospholipids was quantified by gas chromatography mass spectrometry. Results: In CF patients with liver cirrhosis, the levels of C16:0 were higher and the amounts of C20:2n-6, C20:3n-6, C20:4n-6, and all the n-3 polyunsaturated FAs (PUFAs) (C18:3n-3, C20:5n-3, C22:5n-3, C22:6n-3) were lower than those in CF subjects without liver cirrhosis. The n-6/n-3, C20:4n-6/C18:2n-6, total n-6/C18:2n-6, C20:5n-3/C18:3n-3 and total n-3/C18:3n-3 ratios did not differ between the 2 groups. Conclusions: Liver cirrhosis may associate with profound abnormalities in the composition of serum glycerophospholipids FAs in CF patients. None of the analyzed clinical factors could explain the greater prevalence of low levels of PUFAs in this CF subgroup.

Complex Relation Between Diet and Phospholipid Fatty Acids in Children With Cystic Fibrosis

OBJECTIVES

Altered total plasma n-6 and n-3 fatty acids are common in cystic fibrosis (CF). Whether alterations extend to plasma phosphatidylcholine (PC) and phosphatidylethanolamine (PE) and are explained by diet is unclear. The present study was to describe the dietary intake of a large group of children with CF and to determine whether dietary fat composition explains differences in plasma PC and PE fatty acids between children with and without CF.

METHODS

Dietary intake was assessed using a food frequency questionnaire. Venous blood was collected. Plasma PC and PE were separately analyzed for fatty acids.

RESULTS

Children with CF, n = 74, consumed more calories and fat (g/day and % energy), with significantly more saturates mainly from dairy foods and less polyunsaturates including linoleic acid (LA), arachidonic acid (ARA), eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA) (% fat) than reference children, n = 71. A subset of children with CF, not differing in dietary intake from the larger group, had significantly lower LA and DHA, but higher EPA in plasma PC and had higher LA and lower ARA and DHA in plasma PE, compared to a subset of reference children. In both groups, LA intake and LA in plasma PC and PE were not associated. EPA and DHA intakes were positively associated with EPA and DHA, respectively, in plasma PC, but not PE, in reference children only.

CONCLUSIONS

The fatty acid composition of plasma PC and PE is altered in CF. Fatty acid differences between children with and without CF are inconsistent between PC and PE and are not explained by dietary fat.

Determinants of Serum Glycerophospholipid Fatty Acids in Cystic Fibrosis

The etiology of altered blood fatty acid (FA) composition in cystic fibrosis (CF) is understood only partially. We aimed to investigate the determinants of serum glycerophospholipids’ FAs in CF with regard to the highest number of FAs and in the largest cohort to date. The study comprised 172 CF patients and 30 healthy subjects (HS). We assessed Fas’ profile (gas chromatography/mass spectrometry), CF transmembrane conductance regulator (CFTR) genotype, spirometry, fecal elastase-1, body height and weight Z-scores, liver disease, diabetes and colonization by Pseudomonas aeruginosa. The amounts of saturated FAs (C14:0, C16:0) and monounsaturated FAs (C16:1n-7, C18:1n-9, C20:1n-9, C20:3n-9) were significantly higher in CF patients than in HS. C18:3n-6, C20:3n-6 and C22:4n-6 levels were also higher in CF, but C18:2n-6, C20:2n-6 and C20:4n-6, as well as C22:6n-3, were lower. In a multiple regression analysis, levels of seven FAs were predicted by various sets of factors that included age, genotype, forced expiratory volume in one second, pancreatic status and diabetes. FA composition abnormalities are highly prevalent in CF patients. They seem to be caused by both metabolic disturbances and independent clinical risk factors. Further research into the influence of CFTR mutations on fat metabolism and desaturases’ activity is warranted.

The effects of ivacaftor on CF fatty acid metabolism: An analysis from the GOAL study

BACKGROUND

Ivacaftor has produced significant improvement in certain individuals with cystic fibrosis (CF), though the full metabolic effects of treatment remain unknown. Abnormalities in fatty acid metabolism have previously been shown to be a characteristic of CFTR dysfunction. We hypothesized that as a reflection of this clinical improvement, ivacaftor would improve plasma fatty acid levels and decrease urine prostaglandin E metabolite levels.

METHODS

This study analyzed plasma fatty acid levels and urine prostaglandin E metabolites (PGE-M) in 40 subjects with CF participating in the G551D observational (GOAL) study who demonstrated response to the medication by a significant decrease in sweat Cl levels. Paired samples were analyzed before and after 6months of ivacaftor treatment.

RESULTS

Linoleic acid and docosahexaenoic acid levels, which are typically low in individuals with CF, did not significantly increase with ivacaftor treatment. However, arachidonic acid levels did decrease with ivacaftor treatment and there was a significant decrease in the arachidonic acid metabolite PGE-M as measured in the urine [median: before treatment 17.03ng/mg Cr; after treatment 9.06ng/mg Cr; p<0.001]. Furthermore, there were fatty acid age differences observed, including pediatric participants having significantly greater linoleic acid levels at baseline.

CONCLUSION

Ivacaftor reduces inflammatory PGE without fully correcting the plasma fatty acid abnormalities of CF. Age-related differences in fatty acid levels were observed, that may be a result of other clinical factors, such as diet, clinical care, or drug response.

Chronic pancreatitis and the composition of plasma phosphatidylcholine fatty acids

Chronic pancreatitis (CP) is an irreversible inflammatory disorder characterized by the destruction of both exocrine and endocrine tissue. There is growing evidence that dysregulation of fatty acid (FA) metabolism is connected with many diseases; however, there are few data concerning FA composition in CP. Therefore, we analyzed FA profiles in plasma phosphatidylcholines in 96 patients with CP and in 108 control subjects (CON). The patients with CP had, in comparison with CON, increased sum of monounsaturated FA (ΣMUFA) and decreased content of polyunsaturated FA (PUFA) in both n-6 and n-3 families. Moreover, CP patients had increased indexes for delta-9, delta-6 desaturases, and fall in activity of delta-5 desaturase. Increased ratio of 16:1n-7/18:2n-6 (marker of essential n-6 FA deficiency), was more prevalent among CP patients. These changes implicated decreased fat intake, including n-3 as well as n-6 PUFA, and intrinsic changes in FA metabolism due to the alteration of delta desaturase activities.

Increased ω-3 polyunsaturated fatty acid/arachidonic acid ratios and upregulation of signaling mediator in individuals with autism spectrum disorders

AIMS

The investigation of links between the ratio of omega-3/omega-6 PUFAs and neuronal signaling is a research priority in autism spectrum disorders (ASD).

MAIN METHODS

We examine the relationships between the plasma ratios of docosahexaenoid acid (DHA)/arachidonic acid (AA) and eicopentaenoic acid (EPA)/AA and biomarkers of AA-related signaling mediators such as ceruloplasmin, transferrin and superoxide dismutase, in the behavioral symptoms of 28 individuals with ASD (mean age 13.5±4.6years) and 21 age- and gender-matched normal healthy controls (mean age 13.9±5.7years). Behavioral symptoms were assessed using the Aberrant Behavior Checklists (ABC). We conducted controlling for dietary intake and assessed the dietary intake of nutrients.

KEY FINDINGS

There were no significant differences in intake of nutrients such as omega-3 and omega-6 PUFAs, saturated and unsaturated fatty acid, DHA, AA, iron and copper. Plasma EPA, DHA, and arachidic acid levels, and plasma DHA/AA and EPA/AA ratios were significantly higher, while plasma AA and adrenic acid were significantly lower in the 28 individuals with ASD than in the 21 normal controls. The ABC scores were significantly higher in the ASD group compared to the control group. The plasma ceruloplasmin levels in the ASD group were significantly reduced compared to those in the control group.

SIGNIFICANCE

Increased plasma DHA/AA and EPA/AA ratios may be related to low plasma levels of ceruloplasmin which has neuroprotective properties. Reduced plasma ceruloplasmin levels may diminish the protective capacity against brain damage, and may contribute to the pathophysiology of behavioral symptoms in individuals with ASD.

Down-regulation of a signaling mediator in association with lowered plasma arachidonic acid levels in individuals with autism spectrum disorders

Previous studies have indicated that the altered composition of polyunsaturated fatty acids (PUFAs) might contribute to the pathophysiology of autism spectrum disorder (ASD). We examined the relationship between the plasma fatty acid levels, expressed as μg/ml, and the plasma levels of biomarkers of AA-related signaling mediators, such as ceruloplasmin, transferrin and superoxide dismutase, and assessed the behavioral symptoms of 30 individuals with ASD (mean age, 13.6 ± 4.3 years old) compared with 20 age- and gender-matched normal controls (mean age, 13.2 ± 5.4 years old) using Aberrant Behavior Checklists (ABC). The plasma levels of EPA and the plasma ratios of EPA/AA were significantly higher, while the plasma levels of AA and metabolites, such as 5,8,11,14-eicosatetraenoic acid, adrenic acid, and ceruloplasmin (Cp), were significantly lower in the 30 individuals with ASD compared with the 20 normal controls. The ABC scores were significantly increased in the ASD group compared with those of the control group. Thus, the results of the present study revealed that reduced plasma levels of AA and metabolites in association with high plasma EPA/AA ratios might down-regulate AA-related signaling mediators, such as Cp. Subsequently, reduced plasma Cp levels might reduce the protective capacity for brain damage, resulting in the pathophysiology underlying the behavioral symptoms in individuals with ASD. These findings suggest that reduced plasma AA levels may downregulate Cp.

Inflammation, oxidative stress, and cardiovascular disease risk factors in adults with cystic fibrosis

Cystic fibrosis (CF) represents one of a number of localized lung and non-lung diseases with an intense chronic inflammatory component associated with evidence of systemic oxidative stress. Many of these chronic inflammatory diseases are accompanied by an array of atherosclerotic processes and cardiovascular disease (CVD), another condition strongly related to inflammation and oxidative stress. As a consequence of a dramatic increase in long-lived patients with CF in recent decades, the specter of CVD must be considered in these patients who are now reaching middle age and beyond. Buttressed by recent data documenting that CF patients exhibit evidence of endothelial dysfunction, a recognized precursor of atherosclerosis and CVD, the spectrum of risk factors for CVD in CF is reviewed here. Epidemiological data further characterizing the presence and extent of atherogenic processes in CF patients would seem important to obtain. Such studies should further inform and offer mechanistic insights into how other chronic inflammatory diseases potentiate the processes leading to CVDs.