Tracheal Aspirate as an Alternative Biologic Sample for Pharmacogenomics Testing in Mechanically Ventilated Pediatric Patients.

Patients in the pediatric intensive care unit are exposed to multiple medications and are at high risk for adverse drug reactions. Pharmacogenomic (PGx) testing could help decrease their risk of adverse reactions. Although whole blood is preferred for PGx testing, blood volume in this population is often limited. However, for patients on mechanical ventilation, tracheal secretions are abundant, frequently suctioned, and discarded. Thus, the aim of this pilot study was to determine if tracheal aspirates could be used as a source of human genomic DNA for PGx testing. We successfully extracted DNA from tracheal secretions of all 23 patients in the study. The samples were successfully genotyped for 10 clinically actionable single nucleotide variants across 3 cytochrome P450 genes (CYP2D6, CYP2C19, and CYP3A5). Using DNA from whole blood samples in 11 of the patients, we confirmed the accuracy of the genotyping with 100% concordance. Therefore, our results support the use of tracheal aspirates from mechanically ventilated children as an adequate biospecimen for clinical genetic testing.

Role of PPARα in the attenuation of bile acid-induced apoptosis by omega-3 long-chain polyunsaturated fatty acids in cultured hepatocytes.

BACKGROUND: Omega-3 long-chain polyunsaturated fatty acids (ω3PUFA) have been shown to be antiinflammatory in the attenuation of hepatocellular injury. Peroxisome proliferator-activated receptor alpha (PPARα) is a nuclear receptor transcription factor that inhibits the activation of nuclear factor κB, thereby repressing inflammation, and ωPUFA are PPARα ligands. The purpose of this study was to determine if ω3PUFA attenuate bile acid-induced apoptosis via PPARα. METHODS: Human hepatocellular carcinoma (HepG2) cells were treated with chenodeoxycholic acid (CDCA) ± ω3PUFA. Activation of PPARα was evaluated, and expression of PPARα, farnesoid X receptor, liver X receptor alpha (LXRα), and retinoid X receptor mRNA was evaluated by reverse-transcriptase PCR. RESULTS: PPARα activation was increased in HepG2 cells treated with ω3PUFA, and decreased in the presence of CDCA when compared with untreated cells. PPARα mRNA was reduced by 67% with CDCA and restored to the level of control with ω3PUFA. LXRα mRNA increased twofold with CDCA treatment and was significantly reduced by ω3PUFA. CONCLUSION: Expression of PPARα, as well as LXRα mRNA levels, was reduced with CDCA treatment and restored with the addition of ω3PUFA. These results suggest that PPARα and LXRα may be mediators by which ω3PUFA attenuate bile acid-induced hepatocellular injury.

Review and clinical update on parenteral nutrition-associated liver disease.

Parenteral nutrition-associated liver disease (PNALD) is a complex disease that is diagnosed by clinical presentation, biochemical markers of liver injury, concurrent use of parenteral nutrition (PN), and negative workup for other causes of liver disease. Since the first case of PNALD was reported more than 30 years ago, clinicians have had few effective treatments for PNALD, and when disease progressed to liver cirrhosis, it was historically associated with poor outcomes. Within the past 5 years, there has been much excitement about new treatments for PNALD, including use of both parenteral and enteral ω-3 polyunsaturated long-chain fatty acids (ω-3 PUFA) as well as restricting dosing of ω-6 PUFA. Scientists are also interested in uncovering the mechanisms associated with liver injury seen in PNALD. This article reviews the recent literature relating to the pathophysiology and treatment of PNALD.

Eicosapentaenoic acid and docosahexaenoic acid synergistically attenuate bile acid-induced hepatocellular apoptosis.

BACKGROUND: Clinical studies have demonstrated improvement of parenteral nutrition (PN)-associated liver disease (PNALD) with ω3 polyunsaturated fatty acid (ω3PUFA) supplementation containing eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). Experiments were designed to test the following hypotheses: (1) therapeutic effects of ω3PUFA are due to attenuation of cellular apoptosis induced by hydrophobic bile acid exposure, which occurs in cholestasis, and (2) attenuation of apoptosis by EPA and DHA is additive or synergistic. METHODS: Cultured HepG2 cells were treated with 50-200 µM chenodeoxycholic acid (CDCA) in the presence and absence of EPA, DHA, or EPA + DHA. Apoptosis was evaluated using cell staining with fluorescence microscopy and the Apo-ONE Homogeneous Caspase-3/7 assay. Specific apoptotic mediators were evaluated with quantitative RT-PCR. RESULTS: Treatment with EPA alone and DHA alone resulted in 22% and 9% attenuation of caspase-3/7 activity, respectively. Caspase-3/7 activity was attenuated by 52% when cells were treated with a combination of EPA and DHA (P = .0034). Treatment with EPA alone, DHA alone, and the combination of EPA and DHA all resulted in equal attenuation of apoptotic mediator gene expression. CONCLUSIONS: The combination of EPA and DHA resulted in a synergistic attenuation of bile acid-induced hepatocellular apoptosis, as assessed by caspase-3/7 activity, compared to EPA and DHA separately. The combination of EPA and DHA did not result in a synergistic attenuation of the upregulation of Fas or TRAIL-R2. These data suggest that EPA and DHA may be working via multiple intracellular pathways to attenuate bile acid-induced apoptosis.

Enteral fish oil for treatment of parenteral nutrition-associated liver disease in six infants with short-bowel syndrome.

STUDY OBJECTIVE: To evaluate the use of enteral fish oil for the treatment of parenteral nutrition-associated liver disease (PNALD). DESIGN: Retrospective case series. SETTING: Pediatric academic hospital and outpatient clinic. PATIENTS: Six parenteral nutrition-dependent infants with short-bowel syndrome and PNALD. MEASUREMENTS AND MAIN RESULTS: The six infants received supplementation with enteral fish oil, and treatment was evaluated over a 12-week period. The PNALD, as reflected by elevated total bilirubin levels, completely reversed in four of the six infants within a mean ± SD of 5 ± 2.6 weeks (range 2-8 wks) after initiation of the enteral fish oil supplementation. In addition, improvement in enteral feedings occurred after starting enteral fish oil therapy. CONCLUSION: Enteral fish oil may be an effective adjunctive treatment option for infants with PNALD, particularly for those infants with PNALD who are tolerating some amount of enteral nutrition as the result of an adequate amount of small bowel.

Omega-3 long chain polyunsaturated Fatty acids for treatment of parenteral nutrition-associated liver disease: a review of the literature.

Parenteral nutrition-associated liver disease (PNALD) is a complex disease that is diagnosed by clinical presentation, biochemical markers of liver injury, concurrent use of parenteral nutrition (PN), and negative workup for other causes of liver disease. For the past 30 years, clinicians have had few effective treatments for PNALD and when disease progressed to liver cirrhosis it was historically associated with poor outcomes. Within the past 5 years there has been some encouraging evidence for the potential benefits of fish oils, rich in omega-3 long-chain polyunsaturated fatty acids (ω3PUFA), in reversing liver injury associated with PN. This article reviews the current literature relating to ω3PUFA and PNALD.