Tadalafil therapy for sarcoidosis-associated pulmonary hypertension

Sarcoidosis-associated pulmonary hypertension (SAPH) is estimated to occur in at least 5% or more of sarcoidosis patients, and it contributes to significant morbidity and mortality. Optimal therapy for SAPH is not well established. We performed a 24-week open-label trial of tadalafil for SAPH at 2 academic medical centers. Subjects were required to have confirmed sarcoidosis plus a right heart catheterization within 12 months of enrollment showing a mean pulmonary artery pressure ≥ 25 mmHg, a pulmonary artery wedge pressure ≤ 15 mmHg, and a calculated pulmonary vascular resistance ≥ 3 Wood units. Subjects received 20 mg/day of tadalafil for the first 4 weeks and then 40 mg/day for the subsequent 20 weeks. Sixteen patients were screened, 12 of whom met criteria for enrollment. At 24 weeks, there was no overall improvement in 6-minute walk distance (6MWD). Five of the 12 subjects dropped out of the study early (2 for social reasons, 3 for medical reasons). There was no significant change in short form 36, St. George's respiratory questionnaire, or maximum Borg dyspnea scores over the 24 weeks. There were no significant adverse events or laboratory abnormalities clearly related to tadalafil in the cohort. The study did not meet the primary end point of change in 6MWD because of the small sample size. Tadalafil was generally safely administered in this cohort of SAPH patients. There was a relatively high dropout rate but no major adverse events and no clinical worsening. Larger studies are needed to explore this question further. (Trial registration: ClinicalTrials.gov identifier: NCT01324999).

Ambrisentan for sarcoidosis associated pulmonary hypertension

BACKGROUND

Sarcoidosis associated pulmonary hypertension (SAPH) is associated with significant morbidity and mortality. There is a paucity of information concerning therapy for this condition.

METHODS

We performed a prospective, open-label, proof of concept trial of ambrisentan for SAPH. 21 subjects with SAPH received 5 mg/day of ambrisentan for 4 weeks and then 10/mg day for 20 subsequent weeks.

RESULTS

No significant change was noted in the 6-minute walk distance over the course of the study (mean change between week 0 and 24: 9.8 +/- 54.6 meters, p: NS). There were also no significant differences between weeks 0 and 24 in terms of dyspnea as measured by the modified Borg scale, serum brain naturetic peptide, diffusing capacity, and quality of life as measured by the Short Form-36. There was a high dropout rate: overall: 11/21, 52%; social reasons: 3/21, 14%; medical reasons: 8/21, 38% because of dyspnea: 6/21, 29% and/or edema: 4/21, 19%. Of those who completed the 24 week study (10/21, 48%), there was an improvement in their WHO functional class and a marked improvement in their health related quality of life as measured by the St. George Respiratory questionnaire (-15.3 +/- 25.0). However both these improvments did not reach statistical significance possibly because of the small sample size.

CONCLUSION

Although ambrisentan was not well tolerated by many of these subjects with SAPH, in those who remained in this 24-week trial, improvements in WHO functional class and in health related quality of life suggested a possible benefit of this drug in selected patients.

Everolimus versus azathioprine in maintenance lung transplant recipients: an international, randomized, double-blind clinical trial

Everolimus is a proliferation signal inhibitor with immunosuppressive activity that may reduce the rate of progression of chronic rejection, bronchiolitis obliterans syndrome (BOS), after lung transplantation. In a randomized, double-blind clinical trial, 213 BOS-free maintenance patients received everolimus (3 mg/day) or azathioprine (AZA, 1-3 mg/kg/day) in combination with cyclosporine and corticosteroids. The prospectively defined primary endpoint was the incidence of efficacy failure (decline in FEV1 >15%[deltaFEV1 >15%], graft loss, death or loss to follow-up) at 12 months. Incidence of efficacy failure at 12 months was significantly lower in the everolimus group than AZA (21.8% vs. 33.9%; p = 0.046); at 24 months, rates of efficacy failure became similar between the groups. At 12 months, the everolimus group had significantly reduced incidences of deltaFEV1 >15%, deltaFEV1 >15% with BOS, and acute rejection. At 24 months, only incidence of acute rejection remained significantly less in the everolimus group. Treatment discontinuations (particularly due to adverse events), serious adverse events and high serum creatinine values were more common with everolimus. For the first time, a drug has demonstrated significant slowing of loss in lung function, suggesting that patients kept on prolonged maintenance treatment with everolimus may benefit from replacing AZA with everolimus 3 months after lung transplantation.

Long term results of lung transplantation for cystic fibrosis

OBJECTIVES

We reviewed our experience with lung transplant for cystic fibrosis (CF) over a 10-year period to identify factors influencing long-term survival.

METHODS

One hundred and twenty-three patients with CF have undergone 131 lung transplant procedures at our institution; 114 have had bilateral sequential lung transplants (DLTX) and nine have had bilateral lower lobe transplants from living donors. Three patients had retransplant for acute graft failure, and five had late retransplant for bronchiolitis obliterans syndrome (BOS). Kaplan-Meier survival was calculated for the entire cohort and for subsets at higher risk of death to determine factors predicting a better outcome.

RESULTS

Actuarial survival for the entire group of DLTX CF patients was 81% at 1 year, 59% at 5 years, and 38% at 10 years. Lobar transplant was associated with a poorer survival (37.5% at 1 and 5 years). Among DLTX patients, colonization with Burkholderia cepacia was present in 22 patients and was associated with poorer outcome (1- and 5-year survival 60 and 36% in B. cepacia patients vs. 86 and 64% in non-cepacia patients). DLTX patients younger than age 20 (n=22) had a similar survival to patients age 20 or older (n=90). Being on a ventilator at the time of transplant was not associated with poorer survival (n=8). BOS affects increasing numbers of survivors with time. Five CF patients have been retransplanted due to BOS with one operative death and 1-year survival of 60%.

CONCLUSIONS

DLTX has acceptable long term survival in CF adults and children with end stage disease. CF patients colonized with B. cepacia have a worse outcome but transplantation is still warranted.

Outpatient care of the cystic fibrosis patient after lung transplantation

Lung transplantation has become an accepted treatment for respiratory failure due to cystic fibrosis (CF). Effective means of patient selection, surgical technique, immunosuppression, and post-transplant management permit survival as good as that of transplant patients with other diseases. The new lungs do not acquire the CF ion transport abnormalities but are subject to the usual post-transplant complications. CF problems in other organ systems persist and may be worsened by some of the immunosuppressive regimens. Prolonged survival increases the risk of age-related CF and other complications. Effective medical management requires expert knowledge of CF and lung transplantation and of how their problems interact, and good communications among the participating care teams.

Recurrence of allergic bronchopulmonary aspergillosis in the posttransplant lungs of a cystic fibrosis patient

Cystic fibrosis (CF) is an autosomal recessive disease of exocrine origin. Allergic bronchopulmonary aspergillosis (ABPA) is an immunologic disorder caused by colonization of the airways with Aspergillus fumigatus. A fumigatus has been cultured from posttransplant lungs in CF patients. Colonization of posttransplant lung with Aspergillus is a recognized phenomenon. In this case report, however, we present a patient who developed ABPA both before and after lung transplant. This patient meets the criteria for ABPA based on serologic results. ABPA may be a complication in post-CF lung transplant patients and serologic analysis should be considered when eosinophilia and pulmonary infiltrates or decline in lung function occurs.

Acute and chronic lung allograft rejection during pregnancy

Young women who undergo lung transplantation may regain normal fertility and become pregnant. Currently, little is known about the outcome of pregnancy after lung transplantation. We present a case of pregnancy after bilateral lung transplantation complicated by acute and chronic allograft rejection, resulting in irreversible loss of lung function.

Lung epithelial lining fluid T cell subsets defined by distinct patterns of beta 7 and beta 1 integrin expression

Integrins are heterodimeric cell-surface glycoproteins that mediate cell-cell and cell-matrix adhesion. We previously identified cDNA encoding a novel integrin beta subunit, beta 7, from bronchoalveolar lavage fluid (BALF) leukocytes. The beta 7 subunit protein is now known to associate with at least two integrin alpha subunits on lymphocytes. One beta 7 integrin, alpha 4 beta 7, mediates lymphocyte adhesion to endothelium and to fibronectin. The other known beta 7 integrin, alpha E beta 7, has recently been shown to mediate lymphocyte-epithelial cell adhesion in vitro. We used flow microfluorometry to analyze the expression of alpha 4 beta 7, alpha E beta 7, and other integrins on blood T cells and epithelial lining fluid T cells obtained from five healthy adult volunteers by bronchoalveolar lavage. alpha 4 beta 7 was the predominant beta 7 integrin on blood T cells, whereas alpha E beta 7 was predominant on BALF T cells. BALF T cells could be divided into alpha E beta 7- and alpha E beta 7+ subsets. Between 29 and 61% (mean 42%) of CD3+ T cells were alpha E beta 7+ alpha E beta 7 was more likely to be present on CD8+ T cells (mean 69% alpha E beta 7+) than on CD4+ T cells (mean 29% alpha E beta 7+). The alpha E beta 7- and alpha E beta 7+ BALF T cell subsets were also found to differ in their expression of other integrins.(ABSTRACT TRUNCATED AT 250 WORDS)

Enhanced C 2 Yields from Methane Oxidative Coupling by Means of a Separative Chemical Reactor

Of the processes for converting natural gas into a more useful chemical feedstock, the oxidative coupling of methane to form ethane and ethylene (C(2)) has perhaps been the most intensively investigated in recent years, but it has proved extremely difficult to obtain C(2) yields in excess of 20 to 25%. Methane oxidative coupling was carried out in a separative chemical reactor that simulated a countercurrent chromatographic moving-bed. This reaction gives 65% methane conversion, 80% C(2) selectivity, and a C(2) yield slightly better than 50% with Sm(2)O(3) catalyst at approximately 1000 K.

Effects of nitric acid gas alone or in combination with ozone on healthy volunteers

Nitric acid (HNO3) is the most prevalent acid air pollutant in the western United States and has the potential to cause adverse respiratory effects through both acidification and oxidation reactions. To study this potential, we measured physiologic (specific airway resistance, SRaw, FEV1, and FVC) and bronchoalveolar lavage (total and differential cell counts, LDH, fibronectin, and total protein) end points in a group of 10 healthy, athletic subjects who were exposed to 500 micrograms/m3 of HNO3 gas or filtered air for 4 h during moderate exercise (ventilatory rate, 40 L/min) and underwent bronchoscopy 18 h later. Under an identical protocol, 10 healthy subjects were exposed to 500 micrograms/m3 of HNO3 gas plus 0.20 ppm ozone (O3) or 0.20 ppm O3 alone to determine if HNO3 might enhance the toxicity of O3. In addition to bronchoalveolar lavage (BAL), we employed the techniques of isolated left mainstem bronchial lavage and bronchial biopsy to determine if proximal airway injury was caused by pollutant exposure and whether there was any correlation with the degree of distal lung injury as assessed by BAL. We found no significant differences in pulmonary function tests or in the cellular or biochemical constituents in either the BAL or the left mainstem lavage fluids between the HNO3 and the air exposures. Similarly, there were no differences in these end points between the HNO3/O3 and the O3 exposures. Furthermore, there were no significant differences in the bronchial biopsy specimens between the HNO3 and air exposures or between the HNO3/O3 and O3 exposures.(ABSTRACT TRUNCATED AT 250 WORDS)

Lack of bronchoconstrictor response to sulfuric acid aerosols and fogs

Sulfuric acid (H2SO4) is the most common acid air pollutant in the United States and is thought to have adverse respiratory effects. Sulfuric acid exists in polluted air as a dissolved solute in both small (haze) and large (fog) particles. Previous work in our laboratory has failed to demonstrate bronchoconstriction after near ambient, large-particle H2SO4 exposure in subjects with asthma. However, other investigators have found slight but significant changes in lung function following inhalation of small-particle or small-particle, low-relative-humidity (RH) H2SO4 aerosols, leading us to hypothesize that particle size and/or RH may be important variables in acid aerosol exposure. We initially studied the effects of resting inhalation of large-particle (volume median diameter, VMD, approximately equal to 6 microns) and small-particle (VMD approximately equal to 0.4 microns) aerosols with an H2SO4 concentration of 3 mg/m3 through a mouthpiece and found no effect on specific airway resistance (SRaw) or symptom scores. In a second mouthpiece study designed to compare high-RH (100%), large-particle (VMD approximately equal to 6 microns) and low-RH (less than 10%), small-particle (VMD approximately equal to 0.3 microns) aerosols with an H2SO4 concentration of 3 mg/m3, we again found no effect of either aerosol. We then examined the effects of small-particle aerosols inhaled in dry air during moderate exercise. Although breathing low-RH air during exercise provoked increases in SRaw in almost all subjects, this could not be attributed to H2SO4 since low-RH saline aerosol produced a similar result.(ABSTRACT TRUNCATED AT 250 WORDS)

The effects of sequential exposure to acidic fog and ozone on pulmonary function in exercising subjects

In Southern California coastal regions, morning fog is often acidified by the presence of nitric acid (HNO3). Peak exposure to ozone (O3) usually occurs in the afternoon and evening, after the fog has dissipated. To determine whether fog containing HNO3 might enhance pulmonary responses to O3, we studied a group of healthy, athletic subjects selected for lung function sensitivity to O3. On 3 separate days, the subjects exercised for 2 h in atmospheres containing HNO3 fog (0.5 mg/ml), H2O fog, or clean, filtered air. After a 1-h break, they exercised for an additional 3 h in an atmosphere containing 0.20 ppm O3. Surprisingly, the mean O3-induced decrements in FEV1 and FVC were smaller after exercise in each fog-containing atmosphere than they were after exercise in clean, filtered air. The mean (+/- SEM) O3-induced decrements in FEV1 were 26.4 +/- 5.3% after air, 17.1 +/- 3.7% after H2O fog, and 18.0 +/- 4.3% after HNO3 fog, and in FVC they were 19.9 +/- 4.7% after air, 13.6 +/- 2.8% after H2O fog, and 13.6 +/- 4.2% after HNO3 fog.(ABSTRACT TRUNCATED AT 250 WORDS)

Acid fog-induced bronchoconstriction. The role of hydroxymethanesulfonic acid

Hydroxymethanesulfonate (HMSA), the bisulfite (HSO3-) adduct of formaldehyde (CH2O), is a common constituent of California acid fogs. HMSA, most stable in a fog pH range of 3 to 5, dissociates at 6.6, the pH of the fluid lining human airways. The dissociation of inhaled HMSA should theoretically generate sulfur dioxide and CH2O, both of which have bronchoconstrictor potential. Thus, we hypothesized that HMSA may have a specific bronchoconstrictor effect independent of its strength as an acid. To determine whether HMSA has such an effect, 19 subjects with mild to moderate asthma were studied using two different protocols. Initially, a mouthpiece study was performed in which 9 subjects, on 2 separate days, inhaled five aerosols containing either sequentially increasing concentrations (0, 30, 100, 300, and 1000 microM) of HMSA in 50 microM sulfuric acid (H2SO4) or 50 microM H2SO4 alone. The subjects inhaled each aerosol for 3 min during tidal breathing at rest. Specific airway resistance (SRaw) was measured before and after each 3-min exposure. There were no significant differences in the mean changes in SRaw among the various aerosol exposures. To confirm this lack of bronchoconstrictor effect of HMSA, we then performed a chamber study in which 10 freely breathing, intermittently exercising subjects were exposed to fog containing either 1 mM HMSA in 5 mM H2SO4 or 5 mM H2SO4 alone for 1 h. SRaw was measured before, during, and at the end of the 1-h exposure.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of cell motility and chemotaxis on microbial population growth

A mathematical model is developed to elucidate the effects of biophysical transport processes (nutrient diffusion, cell motility, and chemotaxis) along with biochemical reaction processes (cell growth and death, nutrient uptake) upon steady-state bacterial population growth in a finite one-dimensional region. The particular situation considered is that of growth limitation by a nutrient diffusing from an adjacent phase not accessible to the bacteria. It is demonstrated that the cell motility and chemotaxis properties can have great influence on steady-state population size. In fact, motility effects can be as significant as growth kinetic effects, in a manner analogous to diffusion- and reaction-limited regimes in chemically reacting systems. In particular, the following conclusions can be drawn from our analysis for bacterial populations growing at steady-state in a confined, unmixed region: (a) Random motility may lead to decreased population density; (b) chemotaxis can allow increased population density if the chemotactic response is large enough; (c) a species with superior motility properties can outgrow a species with superior growth kinetic properties; (d) motility effects become greater as the size of the confined growth region increases; and (e) motility effects are diminished by significant mass-transfer limitation of the nutrient from the adjacent source phase. The relationships of these results for populations to previous conclusions for individual cells is discussed, and implications for microbial competition are suggested.

Effects of random motility on growth of bacterial populations

A spatially distributed mathematical model is developed to elucidate the effects of chemical diffusion and cell motility as well as cell growth, death, and substrate uptake on steady-state bacterial population growth in a finite, one-dimensional, nonmixed region. The situation considered is growth limited by a diffusing substrate from an adjacent phase not accessible to the bacteria. Chemotactic movement is not considered in this paper; we consider only "randomwalk"-type random motility behavior here. The following important general concepts are suggested by the results of our theoretical analysis: (a) The significance of random motility effects depends on the magnitude of the ratioμ/kL (2), whereμ is the bacterial random motility coefficient,k is the growth rate constant, andL is the linear dimension of the confined growth region. (b) In steady-state growth in a confined region, the bacterial population size decreases asμ increases. (c) The effect ofμ on population size can be great; in fact, sometimes relative population sizes of two species can be governed primarily by the relative values ofμ rather than by the relative values ofk.