Impact of elexacaftor/tezacaftor/ivacaftor on respiratory colonization in an adult cystic fibrosis clinic.

BACKGROUND: Little research has been completed on the correlation between cystic fibrosis (CF) modulator therapy and its effect on respiratory cultures in CF patients. This study evaluated the effect of elexacaftor/tezacaftor/ivacaftor (ETI) on respiratory colonization with Pseudomonas aeruginosa. METHODS: This single center, IRB approved, retrospective chart review compared patient data two years immediately prior to ETI initiation with patient data two years post-initiation from January 2017-December 2022. Patients were included in the study if they were at least 18 years old with a diagnosis of CF and had at least one month of ETI dispensed, at least one sputum culture obtained, and were currently on ETI. Those who had not been seen since ETI initiation or received a bilateral lung transplant were excluded. The primary outcome was rate of patients with respiratory colonization post-ETI. Colonization was defined as two or more positive P. aeruginosa cultures in a 12-month period. Decolonization was defined as three consecutive negative P. aeruginosa cultures after previous colonization. Key secondary outcomes included average time to discontinuation of mucolytic therapy and relative risk of pulmonary exacerbation. RESULTS: A significant reduction (p<0.001) in colonization with P. aeruginosa was observed with 49 patients in the pre-ETI group compared to 25 in the post-ETI group meeting the definition of colonization (n=79). Average time to discontinuation of mucolytic therapy was 14 months (p=0.002). Relative risk of pulmonary exacerbation was 4.80 (p<0.001). CONCLUSIONS: ETI use resulted in reduced colonization with P. aeruginosa, discontinuation of mucolytic therapy, and decreased frequency of pulmonary exacerbation.

Immunosuppression maintenance in vascularized composite allotransplantation: what is just right?

PURPOSE OF REVIEW: Over the last two decades advances in vascularized composite allotransplantation have achieved clinically significant milestones. This review provides a synopsis for immunosuppressive maintenance therapy for VCA and discusses the nuances surrounding the determination of the right amount of immunosuppression in vascularized composite allotransplantation. RECENT FINDINGS: Functional results after vascularized composite allotransplantation remain highly encouraging as are the immunologic outcomes, however, challenges persist. Currently, although conventional immunosuppressive protocols have been successful at preventing allograft loss; they have not totally prevented episodes of acute rejection in the skin. Furthermore, vascularized composite allotransplantation carries a significant risk profile attributed to the complications of life-long, high-dose immunosuppression regimens. SUMMARY: Examining conventional treatment protocols can lead to the development of novel immunosuppression concepts that will ultimately assist in favorably tilting the risk-benefit scale for these life-changing transplants.

Surgical correction of gastroesophageal reflux in lung transplant patients is associated with decreased effector CD8 cells in lung lavages: a case series.

BACKGROUND: Lung transplantation is associated with a high incidence of gastroesophageal reflux disease (GERD). The presence of GERD is considered a risk factor for the subsequent development of obliterative bronchiolitis (OB), and surgical correction of GERD by gastric fundoplication (GF) may be associated with increased freedom from OB. The mechanisms underlying a protective effect from OB remain elusive. The objective of this study was to analyze the flow cytometric properties of BAL cells in patients who have undergone GF early after transplant. METHODS: In a single-center lung transplant center, eight patients with GERD who were in the first transplant year underwent GF. Prior to and immediately following GF, BAL cells were analyzed by polychromatic flow cytometry. Spirometry was performed before and after GF. RESULTS: GF was associated with a significant reduction in the frequency of BAL CD8 lymphocytes expressing the intracellular effector marker granzyme B, compared with the pre-GF levels. Twenty-six percent of CD8 cells were granzyme Bhi pre-GF compared with 12% of CD8 cells post-GF (range 8%-50% pre-GF, 2%-24% post-GF, P = .01). In contrast, GF was associated with a significant interval increase in the frequency of CD8 cells with an exhausted phenotype (granzyme Blo, CD127lo, PD1hi) from 12% of CD8 cells pre-GF to 24% post-GF (range 1.7%-24% pre-GF and 11%-47% post-GF, P = .05). No significant changes in spirometry were observed during the study interval. CONCLUSIONS: Surgical correction of GF is associated with a decreased frequency of potentially injurious effector CD8 cells in the BAL of lung transplant recipients.

Vitamin D inhibition of pro-fibrotic effects of transforming growth factor beta1 in lung fibroblasts and epithelial cells.

The mechanisms that control fibroproliferation and matrix deposition in lung fibrosis remain unclear. We speculate that vitamin D deficiency may contribute to pulmonary fibrosis since vitamin D deficiency has been implicated in several diseases. First, we confirmed the presence of vitamin D receptors (VDRs) in cultured NIH/3T3 and lung fibroblasts. Fibroblasts transfected with a vitamin D response element-reporter construct and exposed to the active vitamin D metabolite, 1,25(OH)(2)D(3), showed increased promoter activity indicating VDR functionality in these cells. Testing the effects of 1,25(OH)(2)D(3) on fibroblasts treated with transforming growth factor beta1 (TGFbeta1), considered a driver of many fibrotic disorders, we found that 1,25(OH)(2)D(3) inhibited TGFbeta1-induced fibroblast proliferation in a dose-dependent fashion. 1,25(OH)(2)D(3) also inhibited TGFbeta1 stimulation of alpha-smooth muscle actin expression and polymerization and prevented the upregulation of fibronectin and collagen in TGFbeta1-treated fibroblasts. Finally, we examined how 1,25(OH)(2)D(3) affects epithelial-mesenchymal transformation of lung epithelial cells upon exposure to TGFbeta1. We showed that the TGFbeta1-induced upregulation of mesenchymal cell markers and abnormal expression of epithelial cell markers were blunted by 1,25(OH)(2)D(3). These observations suggest that under TGFbeta1 stimulation, 1,25(OH)(2)D(3) inhibits the pro-fibrotic phenotype of lung fibroblasts and epithelial cells.

Efficacy of oral ribavirin in lung transplant patients with respiratory syncytial virus lower respiratory tract infection.

BACKGROUND: Respiratory syncytial virus (RSV) can cause severe lower respiratory tract infection (LRI) and is a risk factor for the development of bronchiolitis obliterans syndrome (BOS) after lung transplantation (LTx). Currently, the most widely used therapy for RSV is inhaled ribavirin. However, this therapy is costly and cumbersome. We investigated the utility of using oral ribavirin for the treatment of RSV infection after LTx. METHODS: RSV was identified in nasopharyngeal swabs (NPS) or bronchoalveolar lavage (BAL) using direct fluorescent antibody (DFA) in 5 symptomatic LTx patients diagnosed with LRI. Data were collected from December 2005 and August 2007 and included: age; gender; type of LTx; underlying disease; date of RSV; pulmonary function prior to, during and up to 565 days post-RSV infection; need for mechanical ventilation; concurrent infections; and radiographic features. Patients received oral ribavirin for 10 days with solumedrol (10 to 15 mg/kg/day intravenously) for 3 days, until repeat NPS were negative. RESULTS: Five patients had their RSV-LRI diagnosis made at a median of 300 days post-LTx. Mean forced expiratory volume in 1 second (FEV(1)) fell 21% (p < 0.012) during infection. After treatment, FEV(1) returned to baseline and was maintained at follow-up of 565 days. There were no complications and no deaths with oral therapy. A 10-day course of oral ribavirin cost $700 compared with $14,000 for nebulized ribavirin at 6 g/day. CONCLUSIONS: Treatment of RSV after LTx with oral ribavirin and corticosteroids is well tolerated, effective and less costly than inhaled ribavirin. Further studies are needed to directly compare the long-term efficacy of oral vs nebulized therapy for RSV.

Oxidation of extracellular cysteine/cystine redox state in bleomycin-induced lung fibrosis.

Several lines of evidence indicate that depletion of glutathione (GSH), a critical thiol antioxidant, is associated with the pathogenesis of idiopathic pulmonary fibrosis (IPF). However, GSH synthesis depends on the amino acid cysteine (Cys), and relatively little is known about the regulation of Cys in fibrosis. Cys and its disulfide, cystine (CySS), constitute the most abundant low-molecular weight thiol/disulfide redox couple in the plasma, and the Cys/CySS redox state (E(h) Cys/CySS) is oxidized in association with age and smoking, known risk factors for IPF. Furthermore, oxidized E(h) Cys/CySS in the culture media of lung fibroblasts stimulates proliferation and expression of transitional matrix components. The present study was undertaken to determine whether bleomycin-induced lung fibrosis is associated with a decrease in Cys and/or an oxidation of the Cys/CySS redox state and to determine whether these changes were associated with changes in E(h) GSH/glutathione disulfide (GSSG). We observed distinct effects on plasma GSH and Cys redox systems during the progression of bleomycin-induced lung injury. Plasma E(h) GSH/GSSG was selectively oxidized during the proinflammatory phase, whereas oxidation of E(h) Cys/CySS occurred at the fibrotic phase. In the epithelial lining fluid, oxidation of E(h) Cys/CySS was due to decreased food intake. Thus the data show that decreased precursor availability and enhanced oxidation of Cys each contribute to the oxidation of extracellular Cys/CySS redox state in bleomycin-induced lung fibrosis.

Bilateral lung transplant with pulmonary thromboendarterectomy for Eisenmenger's syndrome.

Patients with secondary pulmonary hypertension frequently present for evaluation for lung transplantation. In some of these patients, Eisenmenger's syndrome has developed from chronic left to right intracardiac shunts. A smaller group of these patients will also have associated pulmonary artery aneurysms. There is a paucity of literature discussing this topic, however, and currents reports have suggested the need to replace the abnormal pulmonary artery. This paper discusses a patient in whom Eisenmenger's syndrome developed from an atrial septal defect, and resultant pulmonary artery aneurysms and mural thrombi, who underwent successful bilateral lung transplantation with thromboendarterectomy and atrial septal defect closure.

Activation of Tissue Remodeling Precedes Obliterative Bronchiolitis in Lung Transplant Recipients.

Obliterative bronchiolitis (OB) and Bronchiolitis Obliterans Syndrome (BOS) are frequent complications in the lung transplant recipient, and are the leading cause of mortality after transplantation. The mechanisms responsible for OB remain elusive, but inflammatory and tissue remodeling responses are implicated. We hypothesized that alterations in markers of tissue remodeling in BALF of lung transplant recipients could predict development of OB. To test this, we identified 13 lung transplant recipients who developed both BOS and histologic OB (OB group) at median post-operative day (POD) 485 (range 73-2070). Bronchoalveolar lavage fluid (BALF) was obtained at median POD 387 (range 45-2205), which preceded the onset of OB and BOS by a median of 140 days (range 60-365). As a control, BALF was also obtained from a group of 21 stable recipients without OB (non-OB group) at median POD 335 (range 270-395). BALF was examined for gelatinolytic activity, fibronectin gene transcription, and transforming growth factor-beta1 (TGF-beta1) expression. Gelatin zymography of BALF from the OB group showed increased matrix metalloproteinase-9 (MMP-9) activity over that of the non-OB group (p < 0.005). Similarly, BALF from the OB group induced greater fibronectin expression in fibroblasts compared to the non-OB group (p < 0.03). The induction of fibronectin also correlated with the amount of TGF-beta1 protein in BALF (r = 0.71) from the OB group. We conclude that activation of tissue remodeling precedes the onset of OB, and analysis of gelatinolytic and/or fibronectin-inducing activity in BALF can serve as an early, pre-clinical marker for OB.

Outcomes of delayed chest closure after bilateral lung transplantation.

BACKGROUND: Delayed chest closure (DCC) may be used after bilateral lung transplantation when significant bleeding/coagulopathy or severe pulmonary edema exists. Primary chest closure (PCC) in these patients can lead to heart and lung compression causing cardiopulmonary instability. The purpose of this study is to describe factors associated with DCC and evaluate outcomes after DCC. METHODS: We performed a retrospective review of all patients undergoing bilateral lung transplantation between September 2003 and March 2005. Statistical significance was determined by two-tailed t test or Fisher's exact test. RESULTS: Twenty-eight bilateral lung transplantations were performed. Indication for transplant was chronic obstructive pulmonary disease (13), pulmonary fibrosis (5), cystic fibrosis (5), sarcoidosis (3), and pulmonary hypertension (1). Seven patients (25%) required DCC. Mean time to DCC was 5.3 days. Six patients (86%) with DCC required tracheostomy versus 4 patients (20%) with PCC (p = 0.003). Mean days to discharge was 44 in the DCC group and 21 in the PCC group (p = 0.03). Thirty-day survival was 100% in the DCC group and 95% in the PCC group (p = 1.0). There were no wound infections in either group, and 1 patient in the PCC group had sternal nonunion. Delayed chest closure was associated with cardiopulmonary bypass use (p = 0.006), cardiopulmonary bypass time longer than mean cardiopulmonary bypass time (mean, 224 minutes; p = 0.04), PaO2/FiO2 less than mean + 1 SD (value = 4.63, p = 0.0002), evidence of moderate/severe reperfusion injury on chest radiograph (p = 0.0002), and PaO2/FiO2 less than mean plus moderate/severe reperfusion injury on chest radiograph (p = 0.002). CONCLUSIONS: Cardiopulmonary bypass use, prolonged cardiopulmonary bypass time, and significant reperfusion injury, as determined by chest radiograph and a low PaO2/FiO2 ratio were all associated with an increased incidence of DCC in our bilateral lung transplantation patients. These patients had no wound infections or sternal complications, and although they had longer hospital stays than PCC patients, DCC did not affect operative survival. Delayed chest closure can be employed safely, when necessary, after bilateral lung transplantation with outcomes similar to patients with PCC.

Smad3 deficiency ameliorates experimental obliterative bronchiolitis in a heterotopic tracheal transplantation model.

Chronic allograft rejection manifested as obliterative bronchiolitis (OB) remains the single greatest impediment to long-term survival after lung transplantation. Transforming growth factor-beta1 (TGF-beta1) has been implicated in the tissue remodeling response associated with OB. Therefore, its intracellular signal transducer, Smad3, is a prime target of investigation. Herein, we examine the role of TGF-beta1, through Smad3, in the development of OB using heterotopic tracheal transplantation in wild-type and Smad3-null mice. TGF-beta1 was detectable within infiltrating mononuclear cells early after transplantation. Later it was detected in fibroblasts and in the connective tissue accumulating within the lumen and the airway wall of the transplanted allografts. Connective tissue growth factor had a similar time and tissue distribution. Nuclear detection of Smad3 and phosphorylated Smads within intraluminal fibroblasts coincided with increased intraluminal deposition of fibronectin and collagen. When transplanted into Smad3-null mice, allografts failed to organize the intraluminal exudates despite fibroblast accumulation and showed reduced fibronectin and collagen deposition. In culture, Smad3-deficient fibroblasts expressed reduced fibronectin in response to TGF-beta1 compared to wild-type cells. Together, these studies suggest that the TGF-beta signal transducer, Smad3, is required for the development of experimental OB in transplanted tracheas.