Respiratory and sleep disorders in mucopolysaccharidosis.

MPS encompasses a group of rare lysosomal storage disorders that are associated with the accumulation of glycosaminoglycans (GAG) in organs and tissues. This accumulation can lead to the progressive development of a variety of clinical manifestations. Ear, nose, throat (ENT) and respiratory problems are very common in patients with MPS and are often among the first symptoms to appear. Typical features of MPS include upper and lower airway obstruction and restrictive pulmonary disease, which can lead to chronic rhinosinusitis or chronic ear infections, recurrent upper and lower respiratory tract infections, obstructive sleep apnoea, impaired exercise tolerance, and respiratory failure. This review provides a detailed overview of the ENT and respiratory manifestations that can occur in patients with MPS and discusses the issues related to their evaluation and management.

International survey of physician recommendation for tracheostomy for Spinal Muscular Atrophy Type I.

The ethics of invasive mechanical ventilation for children with the neurodegenerative disease Spinal Muscular Atrophy Type I (SMA I) is highly debated, and wide variability in clinical outcomes exists internationally. We conducted this international survey to identify physician characteristics associated with recommendation for tracheostomy and ventilation for SMA I. A cross-sectional online survey was distributed to 1,772 pediatric pulmonologists and pediatric intensivists from online membership directories of American Thoracic Society, American College of Chest Physicians, and European Respiratory Society. Questions explored physician demographics, attitudes and experience with SMA and end-of-life care, knowledge of consensus guidelines, and recommendations for respiratory care of SMA I. A logistic regression model assessed the independent effects of physician variables on the recommendation for invasive ventilation for SMA I. A total of 367 (21%) physicians completed the survey; 82% were pediatric pulmonologists; and 16% pediatric intensivists. Seventy percent of respondents were from the U.S. Fifty percent of physicians were aware of SMA consensus guidelines. Physicians from Commonwealth countries (U.K., Canada, Australia, etc.) were less likely to recommend tracheostomy/ventilation than U.S. physicians (7% vs. 25%, P = 0.005). Logistic regression modeling identified years of experience, pediatric pulmonology specialty, agreement with a pro-life statement, and recommendation for non-invasive ventilation as predictive of recommendation for long-term invasive ventilation for SMA I. In the largest international survey on this topic, we identified regional differences in physician recommendation for invasive ventilation for children with SMA I. Our data demonstrate a need for increased awareness of consensus guidelines and further dialog about the physician role in variability of care for children with SMA I.

Arginase and arginine dysregulation in asthma.

In recent years, evidence has accumulated indicating that the enzyme arginase, which converts L-arginine into L-ornithine and urea, plays a key role in the pathogenesis of pulmonary disorders such as asthma through dysregulation of L-arginine metabolism and modulation of nitric oxide (NO) homeostasis. Allergic asthma is characterized by airway hyperresponsiveness, inflammation, and remodeling. Through substrate competition, arginase decreases bioavailability of L-arginine for nitric oxide synthase (NOS), thereby limiting NO production with subsequent effects on airway tone and inflammation. By decreasing L-arginine bioavailability, arginase may also contribute to the uncoupling of NOS and the formation of the proinflammatory oxidant peroxynitrite in the airways. Finally, arginase may play a role in the development of chronic airway remodeling through formation of L-ornithine with downstream production of polyamines and L-proline, which are involved in processes of cellular proliferation and collagen deposition. Further research on modulation of arginase activity and L-arginine bioavailability may reveal promising novel therapeutic strategies for asthma.

Asthma in sickle cell disease.

In recent years, evidence has increased that asthma predisposes to complications of sickle cell disease (SCD), such as pain crises, acute chest syndrome, pulmonary hypertension, and stroke, and is associated with increased mortality. An obstructive pattern of pulmonary function, along with a higher-than-expected prevalence of airway hyper-responsiveness (AHR) when compared to the general population, has led some researchers to suspect that underlying hemolysis may contribute to the development of a pulmonary disease similar to asthma in patients with SCD. While the pathophysiologic mechanism in atopic asthma involves up-regulation of Th2 cytokines, mast cell- and eosinophil-driven inflammation, plus increased activity of inducible nitric oxide synthase (iNOS) and arginase in airway epithelium resulting in obstructive changes and AHR, the exact mechanisms of AHR, obstructive and restrictive lung disease in SCD is unclear. It is known that SCD is associated with a proinflammatory state and an enhanced inflammatory response is seen during vaso-occlusive events (VOE). Hemolysis-driven acute-on-chronic inflammation and dysregulated arginine-nitric oxide metabolism are potential mechanisms by which pulmonary dysfunction could occur in patients with SCD. In patients with a genetic predisposition of atopic asthma, these changes are probably more severe and result in increased susceptibility to sickle cell complications. Early recognition and aggressive management of asthma based on established National Institutes of Health asthma guidelines is recommended in order to minimize morbidity and mortality.

EUR-1008 pancreatic enzyme replacement is safe and effective in patients with cystic fibrosis and pancreatic insufficiency.

BACKGROUND: EUR-1008 (Zenpep [pancrelipase]) is a new, enteric-coated, porcine-derived pancreatic enzyme product (PEP) developed for the treatment of cystic fibrosis (CF) patients with malabsorption associated with exocrine pancreatic insufficiency (EPI). Unlike currently marketed PEPs, EUR-1008 contains the label-claimed lipase content. Safety and efficacy were assessed in younger (<7 years) and older (> or =7 years) CF patients with EPI. METHODS: Two multicenter studies were conducted: a randomized, double-blind, placebo-controlled, crossover trial in patients > or =7 years of age (N=34) and a supplemental, open-label study in children <7 years of age (N=19). Use of any medications altering gastric pH/motility was prohibited during the studies. Outcome measures in the randomized trial included changes in the coefficient of fat absorption (CFA), coefficient of nitrogen absorption (CNA), and signs/symptoms of malabsorption for EUR-1008 vs. placebo. Outcome measures in the supplemental study included safety and response (defined as no steatorrhea and no overt signs/symptoms of malabsorption) to EUR-1008 vs. previous enzyme treatment. RESULTS: In the randomized trial, EUR-1008 treatment compared to placebo resulted in a significantly higher mean CFA (88.3% vs. 62.8%, respectively) and CNA (87.2% vs. 65.7%, respectively) (both p<0.001) and reduced the incidence of malabsorption signs and symptoms in 32 evaluable patients. In the supplemental study, 11 of 19 patients met the criteria for responder with EUR-1008 at the end of the study vs. 10 of 19 patients at screening (previous PEP), and improvements in clinical symptoms were reported with EUR-1008 treatment. EUR-1008 was safe and well tolerated, and no serious drug-related AEs were reported in either study. CONCLUSIONS: EUR-1008 was safe, well tolerated, and effective in CF patients of all ages with EPI-associated malabsorption in two clinical trials. Treatment led to clinically and statistically significant improvements in CFA and CNA in the randomized study, and control of malabsorption and clinical symptoms in both studies.