Taurine decreases fecal fatty acid and sterol excretion in cystic fibrosis. A randomized double-blind trial

Blood taurine concentrations in dogs with exocrine pancreatic insufficiency

OBJECTIVE

To determine whether blood taurine concentrations in dogs with exocrine pancreatic insufficiency (EPI) were lower than the reference interval (200 to 350 nmol/mL) or the cutoff used to indicate taurine deficiency (< 150 nmol/mL).

ANIMALS

18 dogs with clinical or presumptive subclinical EPI with residual blood samples available for taurine concentration analysis.

PROCEDURES

Dogs were classified as having clinical EPI if they had a serum trypsin-like immunoreactivity concentration of < 2.0 μg/L and presumptive subclinical EPI if they had a concentration of 2.0 to 5.0 μg/L. Archived, frozen blood samples stored in EDTA were submitted for measurement of taurine concentration with an automated high-performance liquid chromatography amino acid analyzer. Medical record data were examined for associations with blood taurine concentration.

RESULTS

None of the 18 dogs had a blood taurine concentration < 150 nmol/mL. Two dogs had a concentration < 200 nmol/mL. No clinical signs, physical examination findings, or serum biochemical abnormalities were associated with blood taurine concentration. Eleven of the 17 dogs for which diet histories were available were not receiving a diet that met recommendations of the World Small Animal Veterinary Association Global Nutrition Committee.

CONCLUSIONS AND CLINICAL RELEVANCE

A low blood taurine concentration was noted in a small subset of dogs with EPI. Additional research is needed to determine whether EPI was the primary cause of this low concentration. Findings suggested the importance of obtaining complete diet histories and ensuring dietary requirements are sufficiently met in dogs with EPI. (Am J Vet Res 2020;81:958-963).

Interventions for preventing and managing advanced liver disease in cystic fibrosis

BACKGROUND

Cystic fibrosis is an autosomal recessive inherited defect in the cystic fibrosis transmembrane conductance regulator (CFTR) gene resulting in abnormal regulation of salt and water movement across the membranes. In the liver this leads to focal biliary fibrosis resulting in progressive portal hypertension and end-stage liver disease in some individuals. This can be asymptomatic, but may lead to splenomegaly and hypersplenism, development of varices and variceal bleeding, and ascites; it has negative impact on overall nutritional status and respiratory function in this population. Prognosis is poor once significant portal hypertension is established. The role and outcome of various interventions for managing advanced liver disease (non-malignant end stage disease) in people with cystic fibrosis is currently unidentified. This is an updated version of a previously published review.

OBJECTIVES

To review and assess the efficacy of currently available treatment options for preventing and managing advanced liver disease in children and adults with cystic fibrosis.

SEARCH METHODS

We searched the Cochrane Cystic Fibrosis Trials Register, compiled from electronic database searches and handsearching of journals and conference abstract books. Date of last search: 19 November 2019. We also searched the reference lists of relevant articles and reviews and online trials registries. Date of last search: 01 January 2020.

SELECTION CRITERIA

Any published and unpublished randomised controlled trials and quasi-randomised controlled trials of advanced liver disease in cystic fibrosis with cirrhosis or liver failure, portal hypertension or variceal bleeding (or both).

DATA COLLECTION AND ANALYSIS

Authors independently examined titles and abstracts to identify potentially relevant trials, but none were eligible for inclusion in this review.

MAIN RESULTS

A comprehensive search of the literature did not identify any published eligible randomised controlled trials.

AUTHORS' CONCLUSIONS

In order to develop the best source of evidence, there is a need to undertake randomised controlled trials of interventions for preventing and managing advanced liver disease in adults and children with cystic fibrosis.

Interventions for preventing and managing advanced liver disease in cystic fibrosis

BACKGROUND

Cystic fibrosis is an autosomal recessive inherited defect in the cystic fibrosis transmembrane conductance regulator (CFTR) gene resulting in abnormal regulation of salt and water movement across the membranes. In the liver this leads to focal biliary fibrosis resulting in progressive portal hypertension and end-stage liver disease in some individuals. This can be asymptomatic, but may lead to splenomegaly and hypersplenism, development of varices and variceal bleeding, and ascites; it has negative impact on overall nutritional status and respiratory function in this population. Prognosis is poor once significant portal hypertension is established. The role and outcome of various interventions for managing advanced liver disease (non-malignant end stage disease) in people with cystic fibrosis is currently unidentified.

OBJECTIVES

To review and assess the efficacy of currently available treatment options for preventing and managing advanced liver disease in children and adults with cystic fibrosis.

SEARCH METHODS

We searched the Cochrane Cystic Fibrosis Trials Register, compiled from electronic database searches and handsearching of journals and conference abstract books.Date of last search: 06 April 2017.We also searched the reference lists of relevant articles and reviews and online trials registries. Date of last search: 04 January 2017.

SELECTION CRITERIA

Any published and unpublished randomised controlled trials and quasi-randomised controlled trials of advanced liver disease in cystic fibrosis with cirrhosis or liver failure, portal hypertension or variceal bleeding (or both).

DATA COLLECTION AND ANALYSIS

Authors independently examined titles and abstracts to identify potentially relevant trials, but none were eligible for inclusion in this review.

MAIN RESULTS

A comprehensive search of the literature did not identify any published eligible randomised controlled trials.

AUTHORS' CONCLUSIONS

In order to develop the best source of evidence, there is a need to undertake randomised controlled trials of interventions for preventing and managing advanced liver disease in adults and children with cystic fibrosis.

Quality of Reporting Nutritional Randomized Controlled Trials in Patients With Cystic Fibrosis

OBJECTIVE

Randomized controlled trials (RCTs) have a major role in the making of evidence-based guidelines. The aim of the present study was to critically appraise the RCTs that addressed nutritional interventions in patients with cystic fibrosis.

METHODS

Embase, PubMed, and the Cochrane Library were systematically searched until July 2015. Methodology and reporting of nutritional RCTs were evaluated by the Consolidated Standards of Reporting Trials (CONSORT) checklist and additional dimensions relevant to patients with CF.

RESULTS

Fifty-one RCTs were included. Full details on methods were provided in a minority of studies. The mean duration of intervention was <6 months. 56.9% of the RCTs did not define a primary outcome; 70.6% of studies did not provide details on sample size calculation; and only 31.4% reported on the subgroup or separated between important subgroups.

CONCLUSIONS

The examined RCTs were characterized by a weak methodology, a small number of patients with no sample size calculations, a relatively short intervention, and many times did not examine the outcomes that are important to the patient. Improvement over the years has been minor.

Mechanisms Underlying Taurine Protection Against Glutamate-Induced Neurotoxicity

Taurine appears to exert potent protections against glutamate (Glu)-induced injury to neurons, but the underlying molecular mechanisms are not fully understood. The possibly protected targets consist of the plasma membrane and the mitochondrial as well as endoplasmic reticulum (ER) membranes. Protection may be provided through a variety of effects, including the prevention of membrane depolarization, neuronal excitotoxicity and mitochondrial energy failure, increases in intracellular free calcium ([Ca2+]i), activation of calpain, and reduction of Bcl-2 levels. These activities are likely to be linked spatially and temporally in the neuroprotective functions of taurine. In addition, events that occur downstream of Glu stimulation, including altered enzymatic activities, apoptotic pathways, and necrosis triggered by the increased [Ca2+]i, can be inhibited by taurine. This review discusses the possible molecular mechanisms of taurine against Glu-induced neuronal injury, providing a better understanding of the protective processes, which might be helpful in the development of novel interventional strategies.

Persistent fat malabsorption in cystic fibrosis; lessons from patients and mice

Fat malabsorption in pancreatic insufficient cystic fibrosis (CF) patients is classically treated with pancreatic enzyme replacement therapy (PERT). Despite PERT, intestinal fat absorption remains insufficient in most CF patients. Several factors have been suggested to contribute to the persistent fat malabsorption in CF (CFPFM). We reviewed the current insights concerning the proposed causes of CFPFM and the corresponding intervention studies. Most data are obtained from studies in CF patients and CF mice. Based on the reviewed literature, we conclude that alterations in intestinal pH and intestinal mucosal abnormalities are most likely to contribute to CFPFM. The presently available data indicate that acid suppressive drugs and broad spectrum antibiotics could be helpful in individual CF patients for optimizing fat absorption and/or nutritional status.

Risk assessment for the amino acids taurine, L-glutamine and L-arginine

Taurine, glutamine and arginine are examples of amino acids which have become increasingly popular as ingredients in dietary supplements and functional foods and beverages. Animal and human clinical research suggests that oral supplementation of these amino acids provides additional health and/or performance benefits beyond those observed from normal intake of dietary protein. The increased consumer awareness and use of these amino acids as ingredients in dietary supplements and functional foods warrant a comprehensive review of their safety through quantitative risk assessment, and identification of a potential safe upper level of intake. The absence of a systematic pattern of adverse effects in humans in response to orally administered taurine (Tau), l-glutamine (Gln) and l-arginine (Arg) precluded the selection of a no observed adverse effect level (NOAEL) or lowest observed adverse effect level (LOAEL). Therefore, by definition, the usual approach to risk assessment for identification of a tolerable upper level of intake (UL) could not be used. Instead, the newer method described as the Observed Safe Level (OSL) or Highest Observed Intake (HOI) was utilized. The OSL risk assessments indicate that based on the available published human clinical trial data, the evidence for the absence of adverse effects is strong for Tau at supplemental intakes up to 3 g/d, Gln at intakes up to 14 g/d and Arg at intakes up to 20 g/d, and these levels are identified as the respective OSLs for normal healthy adults. Although much higher levels of each of these amino acids have been tested without adverse effects and may be safe, the data for intakes above these levels are not sufficient for a confident conclusion of long-term safety, and therefore these values are not selected as the OSLs.

Diagnosis and treatment of intestinal malabsorption in cystic fibrosis

Intestinal malabsorption is severe and of early onset in virtually all people who have cystic fibrosis. The main cause is deficiency of pancreatic enzymes. Bicarbonate deficiency, abnormal bile salts, mucosal transport problems, motility differences, and anatomical structural changes are other contributory factors. Effective treatment should allow a normal to high-fat diet to be taken, control symptoms, correct malabsorption, and achieve a normal nutritional state and growth. Appropriate pancreatic enzyme replacement therapy will achieve normal or near-normal absorption in most people with cystic fibrosis. Early identification and treatment of intestinal malabsorption is critical to achieving optimal nutritional status. The occurrence of fibrosing colonopathy in a few patients on very high doses of those enzymes which have the copolymer Eudragit L30 D55 in their covering resulted in guidelines in the UK to avoid doses equivalent to more than 10,000 IU lipase per kg per day, and also to avoid preparations containing this copolymer in children and adolescents. For patients not responding to 10,000 IU lipase per kg per day review of adherence to treatment, change of enzyme preparation, variation in time of administration, and reduction in gastric acid may improve absorption. The importance of early investigation to exclude other gastrointestinal disorders as a cause of the patient's symptoms, rather than merely increasing the dose of enzymes, is stressed. With modern pancreatic enzymes in doses up to or only slightly in excess of 10,000 IU lipase per kg per day, adequate control of gastrointestinal symptoms and absorption can be achieved, and a normal nutritional state and growth rate maintained in most people with cystic fibrosis.

Mechanisms of lipid malabsorption in Cystic Fibrosis: the impact of essential fatty acids deficiency

Transport mechanisms, whereby alimentary lipids are digested and packaged into small emulsion particles that enter intestinal cells to be translocated to the plasma in the form of chylomicrons, are impaired in cystic fibrosis. The purpose of this paper is to focus on defects that are related to intraluminal and intracellular events in this life-limiting genetic disorder. Specific evidence is presented to highlight the relationship between fat malabsorption and essential fatty acid deficiency commonly found in patients with cystic fibrosis that are often related to the genotype. Given the interdependency of pulmonary disease, pancreatic insufficiency and nutritional status, greater attention should be paid to the optimal correction of fat malabsorption and essential fatty acid deficiency in order to improve the quality of life and extend the life span of patients with cystic fibrosis.

Nutrition in patients with cystic fibrosis: a European Consensus

This document is the result of an European Consensus conference which took place in Artimino, Tuscany, Italy, in March 2001 involving 33 experts on nutrition in patients with cystic fibrosis, organised by the European Cystic Fibrosis Society, and sponsored by Axcan-Scandipharm, Baxter, Dr Falk Pharma, Fresenius, Nutricia, SHS International, Solvay Pharmaceuticals (major sponsor). The purpose of the conference was to develop a consensus document on nutrition in patients with cystic fibrosis based on current evidence.

Nutritional challenges of infants with cystic fibrosis

Nutrition plays an essential role in the management of cystic fibrosis (CF), particularly in infants with their high energy requirement due to rapid growth. Most infants are already malnourished at the time of clinical diagnosis due to an energy imbalance with increased losses and needs not compensated by energy intake. Even in very young asymptomatic CF patients diagnosed by neonatal screening programs, nutritional deficits can be detected in a high proportion of infants, since about half of all CF patients have evidence of pancreatic insufficiency at the time of birth. This review provides recommendations for assessment of the nutritional status at diagnosis and nutritional management including supplementation with pancreatic enzymes during the first year of life.

Control of malabsorption in cystic fibrosis

Intestinal malabsorption is severe and of early onset in virtually all people who have cystic fibrosis. The main cause is deficiency of pancreatic enzymes, but bicarbonate deficiency, abnormalities of bile salts, mucosal transport and motility, and anatomical structural changes are other contributory factors. Appropriate pancreatic replacement therapy will achieve normal or near normal absorption in many patients. It is important to identify both malabsorption and evidence of a pancreatic lesion in all patients who are to receive pancreatic enzymes. All who have evidence of fat malabsorption are deemed pancreatic insufficient and candidates for enzyme replacement therapy. Effective treatment should allow a normal diet to be taken, control symptoms, correct malabsorption and achieve a normal nutritional state and growth. The occurrence of fibrosing colonopathy in some patients receiving very high doses of those enzymes that have the copolymer Eudragit L30 D55 in their covering has resulted in guidelines in the UK to avoid dosages greater than the equivalent of 10,000 IU lipase/kg/day for all patients and also to avoid preparations containing this copolymer in children and adolescents. For patients not responding to 10,000 IU lipase/kg/day, review of adherence to treatment, change of enzyme preparation, variation of the time of administration and reduction in gastric acid may improve absorption. The importance of excluding other gastrointestinal disorders as a cause of the patient's symptoms and the need for early investigations, rather than merely increasing the dosage of enzymes, is stressed. With modern enzymes, adequate control of gastrointestinal symptoms and absorption can be achieved at dosages of 10,000 IU lipase/kg/day or only slightly more, and a normal nutritional state and growth rate maintained in most patients with cystic fibrosis.

Nutritional imperatives in cystic fibrosis therapy

Patients with CF who receive optimal nutrition have better growth, maintain better nutritional reserves, and have better pulmonary function than patients with CF who have poor nutrition. These factors influence quality of life as well as survival. The metabolic and immunologic response to infection, as well as the increased work of breathing, escalates calorie requirements in this patient population. No single strategy works for every patient. Therefore, close monitoring of growth, symptoms, and changes in respiratory status that could increase calorie requirements is necessary.

Cystic fibrosis. Gastrointestinal complications and gene therapy

The gastrointestinal and nutritional complications of cystic fibrosis are diverse. As longevity improves in patients with cystic fibrosis, management of these complications is becoming increasingly important . This article provides overviews of the molecular aspects of the pathogenesis of cystic fibrosis, the current status of gene therapy, and a review of the gastrointestinal manifestations and nutritional care.

Influence of dietary taurine on vitamin D absorption

To evaluate the influence of dietary taurine supplementation on vitamin D absorption, we studied three groups of infants: 21 (11 preterm) were fed a taurine-free formula, 21 (10 preterm) were fed a taurine-supplemented formula (50 mg/100 g of powder) and 20 (9 preterm) were fed human, not heat-treated milk. Taurine, total bile acids, glyco-(GBA) and tauro-(TBA) conjugated bile acids, 25-hydroxyvitamin D3 (25OHD3) and 1,25-dihydroxyvitamin D3 (1,25OH2D3) were determined in all infants at birth in blood cord and at one and three months of life. In preterm infants fed a taurine-free formula, we found lower plasma taurine levels than in infants of other groups at one and three months of life. In these infants, GBA predominated, with a G/T ratio of 1.1 and 1.4 at one and three months of life, whereas in all other infants TBA predominated with a G/T ratio always < 1. Also, 25OHD3 and 1,25OH2D3 levels were significantly lower in preterm infants fed a taurine-free formula than in infants fed a taurine-enriched formula or human milk. Term infants fed a taurine-free formula did not show differences in the parameters studied in comparison to infants of other groups. Low taurine dietary intake appears to compromise vitamin D absorption in preterm infants, and therefore taurine supplementation of preterm infant formulas should be encouraged.

Ursodeoxycholic acid therapy in cystic fibrosis-associated liver disease: a dose-response study

Previous studies from our groups have demonstrated improvements in biochemical markers of liver function when cystic fibrosis patients with associated liver disease were administered oral ursodeoxycholic acid. The magnitude of the response was somewhat less than that found when comparable doses (10 to 15 mg/kg body wt/day) of ursodeoxycholic acid are given to other liver disease patients; this may be explained by the bile acid malabsorption that is characteristic of the disease. For this reason a dose-response study was carried out in nine cystic fibrosis patients with liver disease to establish whether improved efficacy could be obtained with higher doses. Ursodeoxycholic acid in doses of 5, 10 and 15 mg/kg body wt/day was given orally for consecutive 2-mo periods in a replicated Latin-square design. After this, all patients received 20 mg/kg body wt/day. Liver function, individual serum bile acids and biliary bile acid composition were determined at entry and at the end of each treatment period. Our data demonstrate that the magnitude of the biochemical improvement in serum liver enzymes was significantly greater with higher doses of ursodeoxycholic acid; at 20 mg/kg body wt/day it was similar to that reported for patients with other liver diseases administered lower doses. Biliary ursodeoxycholic acid enrichment increased with increasing doses, attaining 42% +/- 6% of the total biliary bile acids with the highest dose. Fasting serum ursodeoxycholic acid concentrations increased during ursodeoxycholic acid administration but were variable and correlated poorly with the dose of ursodeoxycholic acid administered, whereas no correlation was found between serum ursodeoxycholic acid concentration and the proportion of ursodeoxycholic acid in bile.(ABSTRACT TRUNCATED AT 250 WORDS)