Montelukast for chronic lung allograft dysfunction: Not quite the "Full Monty"

A review of the therapeutic potential of the cysteinyl leukotriene antagonist Montelukast in the treatment of bronchiolitis obliterans syndrome following lung and hematopoietic-stem cell transplantation and its possible mechanisms

Lung and hematopoietic stem cell transplantation are therapeutic modalities in chronic pulmonary and hematological diseases, respectively. One of the complications in these patients is the development of bronchiolitis obliterans syndrome (BOS). The efficacy and safety of available treatment strategies in BOS remain a challenge. A few mechanisms have been recognized for BOS in lung transplant and graft-versus-host disease (GVHD) patients involving the TH-1 and TH-2 cells, NF-kappa B, TGF-b, several cytokines and chemokines, and cysteinyl leukotrienes (CysLT). Montelukast is a highly selective CysLT receptor antagonist that has been demonstrated to exert anti-inflammatory and anti-fibrotic effects in abundant experiments. One area of interest for the use of montelukast is lung transplants or GVHD-associated BOS. Herein, we briefly review data regarding the mechanisms involved in BOS development and montelukast administration as a treatment modality for BOS, and finally, the possible relationship between CysLTs antagonism and BOS improvement will be discussed.

Feasibility and Safety of Low-Dose Mesenchymal Stem Cell Infusion in Lung Transplant Recipients

Background

We have previously shown bone marrow-derived mesenchymal stem cells (MSCs) may shift immune responses toward anti-inflammatory pathways and stabilize the course of obstructive chronic lung allograft syndrome (o-CLAD) after lung transplantation. In this study, we measured the response of lower dose infusions.

Methods

We infused low-dose MSCs intravenously in 13 patients who had developed moderate-to-severe o-CLAD. Three had previously received an infusion of MSCs from a different donor and were re-dosed at 1 × 10⁶ MSC/kg, while 5 received a first dose at 1 × 10⁶ MSC/kg and five received an even lower dose at 0.5 × 10⁶ MSC/kg. We recorded pulmonary function tests before and after infusion, and patients were followed clinically for 12 months.

Results

Infusions were well tolerated, and no significant adverse events were recorded in the first 30 days. There was significant decline (mean ± SD) in forced vital capacity (FVC) (3.49 ± 1.03 vs 3.18 ± 0.94 L, P = .03) and forced expiratory volume in 1 second (FEV1) (2.28 ± 0.86 vs 1.77 ± 0.49 L, P = .04) over the year preceding infusion. FVC (3.18 ± 0.94 vs 3.46 ± 0.99 L, P = .53) and FEV1 was not significantly changed (1.77 ± 0.49 vs 1.88 ± 0.75, P = .72) when comparing values immediately prior to infusion to those obtained 1 year after infusion, indicating a possible stabilizing effect on lung function decline due to o-CLAD.

Conclusion

Intravenous infusions of bone marrow-derived MSCs are well tolerated in lung transplant recipients with moderate-to-severe CLAD. Low-dose MSCs appear to slow progression of CLAD in some patients.

Timing it right: the challenge of recipient selection for lung transplantation

Selection criteria for the referral and potential listing of patients for lung transplantation (LTx) have changed considerably over the last three decades but one key maxim prevails, the ultimate focus is to increase longevity and quality of life by careful utilization of a rare and precious resource, the donor organs. In this article, we review how the changes have developed and the outcomes of those changes, highlighting the impact of the lung allocation score (LAS) system. Major diseases, including interstitial lung disease (ILD), chronic obstructive pulmonary disease and pulmonary hypertension are considered in detail as well as the concept of retransplantation where appropriate. Results from bridging to LTx using extracorporeal membrane oxygenation (ECMO) are discussed and other potential contraindications evaluated such as advanced age, frailty and resistant infections. Given the multiplicity of risk factors it is a credit to those working in the field that such excellent and improving results are obtained with an ongoing dedication to achieving best practice.