Survival benefit of lung transplantation in individuals with severe α1-anti-trypsin deficiency (PiZZ) and emphysema

Pulmonary manifestations of alpha 1 antitrypsin deficiency

Alpha 1 antitrypsin deficiency is a widely under recognized autosomal codominant condition caused by genetic mutations in the SERPINA 1 gene, which encodes for alpha 1 antitrypsin (AAT), a serine protease inhibitor. The SERPINA 1 gene contains 120 variants and mutations in the gene may decrease AAT protein levels or result in dysfunctional proteins. This deficiency leads to unopposed protease activity in tissues, thereby promoting pulmonary and hepatic disease. The most common genotype associated with pulmonary disease is the ZZ genotype, and the most frequent pulmonary manifestation is emphysema. Although its pathophysiology may differ from cigarette smoking related chronic obstructive pulmonary disease, smoking itself can hasten lung decline in alpha 1 antitrypsin deficiency (AATD). The diagnosis of AATD is made through AAT protein testing along with genotyping. AATD patients with obstructive airflow limitation may qualify for intravenous augmentation with AAT. However, there is ongoing research to allow for earlier detection and treatment. This review describes in general terms the genetic mechanisms of AATD; its pathogenesis and the impact of cigarette smoke; and its clinical manifestations, diagnosis, treatment, and prognosis. We hope to stimulate research in the field, but mostly we wish to enhance awareness to promote early diagnosis and treatment in those eligible for intervention.

Personalised indication of augmentation therapy for emphysema associated with severe alpha-1 antitrypsin deficiency: a case series

Severe alpha-1 antitrypsin deficiency (AATD) is associated with an increased risk of emphysema. However, the clinical manifestations are very heterogeneous, and an individual prognosis is very difficult to establish. Intravenous augmentation therapy with alpha-1 antitrypsin (AAT) from pooled blood donors is the only specific treatment available, but it requires weekly or biweekly administration for life. Several guidelines provide the indication criteria for the initiation of AAT augmentation therapy. However, in clinical practice, there are situations in which the decision as to when to start treatment becomes uncertain and some studies have shown great variability in the indication of this treatment even among specialists. The usual dilemma is between initiating augmentation therapy in individuals who may not develop significant lung disease or in whom disease will not progress or delaying it in patients who may otherwise rapidly and irreversibly progress. We illustrate this dilemma with five clinical cases: from the case of a patient with normal lung function who requests initiation of therapy to a moderately stable patient without augmentation or a mild patient who, after several years of remaining stable without treatment, deterioration in lung function initiated and, consequently, augmentation therapy was begun. All the nuances associated with the indication of augmentation justify a personalised approach and the decision about initiating augmentation therapy must be made after careful consideration of the pros and cons with the patient in reference centres with experience in treatment. These reference centres can work in collaboration with local hospitals where patients can be closely followed and augmentation therapy can be administered to avoid unnecessary travelling, making periodical administrations more comfortable for the patient.

Physical Activity, Exercise Capacity and Sedentary Behavior in People with Alpha-1 Antitrypsin Deficiency: A Scoping Review

Alpha-1 antitrypsin deficiency (AATD) is a hereditary disorder and a genetic risk factor for chronic obstructive pulmonary disease (COPD). Physical activity (PA) is important for the prevention and treatment of chronic disease. Little is known about PA in people with AATD. Therefore, we aimed to map the research undertaken to improve and/or measure PA, sedentary behaviour (SB) or exercise in people with AATD. Searches were conducted in CINAHL, Medline, EMBASE and clinical trial databases for studies published in 2021. Databases were searched for keywords (physical activity, AATD, exercise, sedentary behavior) as well as synonyms of these terms, which were connected using Boolean operators. The search yielded 360 records; 37 records were included for review. All included studies (n = 37) assessed exercise capacity; 22 studies reported the use of the six-minute walk test, the incremental shuttle walk test and cardiopulmonary exercise testing were reported in three studies each. Other objective measures of exercise capacity included a submaximal treadmill test, the Naughton protocol treadmill test, cycle ergometer maximal test, endurance shuttle walk test, constant cycle work rate test, a peak work rate test and the number of flights of stairs a participant was able to walk without stopping. A number of participant self-reported measures of exercise capacity were noted. Only one study aimed to analyze the effects of an intensive fitness intervention on daily PA. One further study reported on an exercise intervention and objectively measured PA at baseline. No studies measured SB. The assessment of PA and use of PA as an intervention in AATD is limited, and research into SB absent. Future research should measure PA and SB levels in people with AATD and explore interventions to enhance PA in this susceptible population.

Lung transplantation for COPD/pulmonary emphysema

COPD and α-1 antitrypsin deficiency emphysema remain one of the major indications for lung transplantation. If all other treatment possibilities are exhausted or not possible (including rehabilitation, oxygen therapy, noninvasive ventilation, lung volume reduction), patients may qualify for lung transplantation. Strict selection criteria are implemented with a lot of relative and absolute contraindications. Because of an ongoing donor shortage, only a minority of endstage COPD patients will finally get transplanted. The procedure may involve a single or a double lung transplantation, dependent on the experience of the centre, the waiting list, the availability of donor lungs and the patient's risk-benefit ratio. In general, the life expectancy as well as the health-related quality of life after lung transplantation for COPD are usually increased, and may be somewhat better after double compared with single lung transplantation. Several specific complications can be encountered, such as the development of solid organ cancer and chronic lung allograft dysfunction, which develops in up to 50% of patients within 5 years of their transplant and has a major impact on long-term survival, because of the current inefficient treatment modalities.

[Alpha 1-antitrypsin deficiency]

INTRODUCTION

Pulmonary emphysema and liver disease are the clinical expressions of alpha 1-antitrypsin deficiency, an autosomal recessive genetic disease.

STATE OF THE ART

Alpha 1-antitrypsin deficiency is usually associated with the homozygous Z variant of the SERPINA1 gene. Its clinical expression always consists in a substantial reduction of alpha 1-antitrypsin serum concentration and its variants are analyzed by isoelectric focalization or molecular techniques. Assessed by CO transfer alteration and CT scan, risk of pulmonary emphysema is increased by tobacco consumption. Assessed by transient elastography and liver ultrasound, risk of liver disease is increased by alcohol consumption or obesity. Treatment of COPD-associated alpha 1-antitrypsin deficiency does not differ from that of other forms of COPD. In patients presenting with severe deficiency, augmentation therapy with plasma-derived alpha 1-antitrypsin reduces the progression of emphysema, as shown in terms of CT-based lung density metrics. Patients with alpha 1-antitrypsin deficiency with a ZZ genotype should refrain from alcohol or tobacco consumption, and watch their weight; so should their close relatives.

PERSPECTIVES

Modulation of alpha 1-antitrypsin liver production offers an interesting new therapeutic perspective.

CONCLUSION

Homozygous (Z) variants of the SERPINA1 gene confer an increased risk of pulmonary emphysema and liver disease, particularly among smokers, drinkers and obese persons.

Clinical outcomes and survival following lung transplantation in patients with Alpha-1 antitrypsin deficiency

OBJECTIVE

The primary intention of our study is to describe disease-specific outcomes in patients with alpha-1 antitrypsin deficiency (AATD) following lung transplantation (LT).

METHODS

We reviewed the Organ Procurement and Transplant Network database to identify AATD patients who have undergone LT in the United States.

RESULTS

Two thousand two hundred and thirteen patients with AATD underwent LT between March 1992 and September 2019. A total of 1556 patients received LT with a median age at listing was 51 years. The median time spent on the LT waitlist was 263 days. The median ischemic time was 4.75 h. The Kaplan-Meier survival analysis following LT for AATD patients at 1-, 5-, and 10 years was 82%, 56%, and 34%, at 1-, 5-, and 10 years, respectively. The median survival time post-LT is 6.4 years (Interquartile range 5.6-6.8 years). The post-LT survival was significantly better in double LT compared to single LT (Median 7.7 vs 4.4 years, p < 0.001). Increasing age, presence of CMV mismatch, reintubation prior to discharge, and requiring treatment for rejection within one year of transplantation did impact post-LT mortality.

CONCLUSION

The median survival after LT in AATD is 6.4 years and is similar to other lung diseases. When compared to usual COPD LT, AATD patients have increased post-LT mortality due to infections and liver disease. Recipients of a double lung transplant had a favorable outcome compared to single lung transplant.

Evaluation of targeted versus universal prophylaxis for the prevention of invasive fungal infections following lung transplantation

BACKGROUND

Antifungal prophylaxis to prevent invasive fungal infections (IFI) is widely used following lung transplantation, but the optimal strategy remains unclear. We compared universal with targeted antifungal prophylaxis for effectiveness in preventing IFI.

METHODS

Adult patients who underwent lung transplantation at the University of Michigan from /1 July 2014-31 December 2017 were studied for 18 months post-transplant. Universal prophylaxis consisted of itraconazole with or without inhaled liposomal amphotericin B. Using specific criteria, targeted prophylaxis was given with voriconazole for patients at risk for invasive pulmonary aspergillosis (IPA) and with fluconazole or micafungin for patients at risk for invasive candidiasis. Risk factors, occurrence of proven/probable IFI, and mortality were analyzed for the two prophylaxis cohorts.

RESULTS

Of 105 lung transplant recipients, 84 (80%) received a double lung transplant, and 38 (36%) of patients underwent transplant for pulmonary fibrosis. Fifty-nine (56%) patients received universal antifungal prophylaxis, and 46 (44%), targeted antifungal prophylaxis. Among 20 proven/probable IFI, there were 14 IPA, 4 invasive candidiasis, 1 cryptococcosis, and 1 deep sternal mold infection. Six (10%) IFI occurred in the universal prophylaxis cohort and 14 (30%) in the targeted prophylaxis cohort. Five of 6 (83%) IFI in the universal prophylaxis cohort, compared with 9/14 (64%) in the targeted prophylaxis cohort, were IPA Candida infections occurred only in the targeted prophylaxis cohort. The development of IFI was more likely in the targeted prophylaxis cohort than the universal prophylaxis cohort, HR = 4.32 (1.51-12.38), P = .0064.

CONCLUSIONS

Universal antifungal prophylaxis appears to be more effective than targeted antifungal prophylaxis for prevention of IFI after lung transplant.

Implications of a Change of Paradigm in Alpha1 Antitrypsin Deficiency Augmentation Therapy: From Biochemical to Clinical Efficacy

Ever since the first studies, restoring proteinase imbalance in the lung has traditionally been considered as the main goal of alpha1 antitrypsin (AAT) replacement therapy. This strategy was therefore based on ensuring biochemical efficacy, identifying a protection threshold, and evaluating different dosage regimens. Subsequently, the publication of the results of the main clinical trials showing a decrease in the progression of pulmonary emphysema has led to a debate over a possible change in the main objective of treatment, from biochemical efficacy to clinical efficacy in terms of lung densitometry deterioration prevention. This new paradigm has produced a series controversies and unanswered questions which face clinicians managing AAT deficiency. In this review, the concepts that led to the approval of AAT replacement therapy are reviewed and discussed under a new prism of achieving clinical efficacy, with the reduction of lung deterioration as the main objective. Here, we propose the use of current knowledge and clinical experience to face existing challenges in different clinical scenarios, in order to help clinicians in decision-making, increase interest in the disease, and stimulate research in this field.

Diagnosis and treatment of lung disease associated with alpha one-antitrypsin deficiency: A position statement from the Thoracic Society of Australia and New Zealand

AATD is a common inherited disorder associated with an increased risk of developing pulmonary emphysema and liver disease. Many people with AATD-associated pulmonary emphysema remain undiagnosed and therefore without access to care and counselling specific to the disease. AAT augmentation therapy is available and consists of i.v. infusions of exogenous AAT protein harvested from pooled blood products. Its clinical efficacy has been the subject of some debate and the use of AAT augmentation therapy was recently permitted by regulators in Australia and New Zealand, although treatment is not presently subsidized by the government in either country. The purpose of this position statement is to review the evidence for diagnosis and treatment of AATD-related lung disease with reference to the Australian and New Zealand population. The clinical efficacy and adverse events of AAT augmentation therapy were evaluated by a systematic review, and the GRADE process was employed to move from evidence to recommendation. Other sections address the wide range of issues to be considered in the care of the individual with AATD-related lung disease: when and how to test for AATD, changing diagnostic techniques, monitoring of progression, disease in heterozygous AATD and pharmacological and non-pharmacological therapy including surgical options for severe disease. Consideration is also given to broader issues in AATD that respiratory healthcare staff may encounter: genetic counselling, patient support groups, monitoring for liver disease and the need to establish national registries for people with AATD in Australia and New Zealand.

Prevalence of alpha-1-antitrypsin deficiency carriers in a population with and without colonic diverticula. A multicentre prospective case-control study: the ALADDIN study

PURPOSE

The underling pathophysiological mechanisms that cause the formation of colonic diverticula (diverticulosis) remain unclear. Connective tissue changes due to ageing that cause changes in collagen structure of the colonic wall is one theory. Alpha-1-antitrypsin (A1AT) is a protease inhibitor known to protect connective tissue in other organs. Associations between (carriers of) A1AT deficiency and the development of colonic diverticula will be the main focus of this study.

METHODS

A multicentre prospective case-controlled study. In total, 230 patients ≥ 60 years with acute abdominal pain undergoing an abdominal computed tomography (CT) will be included. The research group consists of patients with diverticulosis and/or diverticulitis; controls are patients without diverticula (0 to ≤ 5 diverticula). Genotype analysis for A1AT deficiency will be performed.

RATIONALE

Hypothetically, connective tissue changes, in particular related to (carriers of) A1AT deficiency, can contribute to the development of diverticula and diverticulitis. We expect to find a higher prevalence of A1AT carriers in patients with diverticulosis compared to patients without diverticulosis. Having diverticulosis does not affect the general health of these individuals per se, when asymptomatic. Once an association is found, present findings can be the basis for a second study to assess the risk of developing acute diverticulitis and its disease course in carriers of A1AT deficiency. Because a large cohort is needed in the latter, we shall first perform a pilot study to investigate the likelihood of the primary hypothesis.

TRIAL REGISTRATION

Netherlands Trial register, NTR6251, NL55016.094.15.

[Selection of lung transplant candidates in France in 2019]

INTRODUCTION

In 2015, the International Society for Heart and Lung Transplantation (ISHLT) published a consensus document for the selection of lung transplant candidates. In the absence of recent French recommendations, this guideline is useful in order to send lung transplant candidates to the transplantation centers and to list them for lung transplantation at the right time.

BACKGROUND

The main indications for lung transplantation in adults are COPD and emphysema, idiopathic pulmonary fibrosis and interstitial diseases, cystic fibrosis and pulmonary arterial hypertension (PAH). The specific indications for each underlying disease as well as the general contraindications have been reviewed in 2015 by the ISHLT. For cystic fibrosis, the main factors are forced expiratory volume in one second, 6-MWD, PAH and clinical deterioration characterized by increased frequency of exacerbations; for emphysema progressive disease, the BODE score, hypercapnia and FEV1; for PAH progressive disease or the need of specific intravenous therapy and NYHA classification. Finally, the diagnosis of fibrosing interstitial lung disease is usually a sufficient indication for lung transplantation assessment.

OUTLOOK AND CONCLUSION

These new recommendations, close to French practices, help clinicians to find the right time for referral of patients to transplantation centers. This is crucial for the prognosis of lung transplantation.

Greater survival despite increased complication rates following lung transplant for alpha-1-antitrypsin deficiency compared to chronic obstructive pulmonary disease

Background

Alpha-1-antitrypsin (A1AT) deficiency (A1ATD) is characterized by accelerated degradation of lung function. We examined our experience with lung transplantation for chronic obstructive pulmonary disease (COPD) with and without A1ATD to compare survival and rates of postoperative surgical complications.

Methods

Patients with A1ATD and non-A1ATD COPD undergoing lung transplantation from 1988-2015 at our institution were analyzed. Complications were categorized into non-gastroenteritis gastrointestinal (GI), wound, airway, and reoperation for bleeding. Overall and complication-free survival were evaluated using Kaplan-Meier curves and Cox proportional hazards models.

Results

Three hundred and eighty-five patients underwent lung transplant for COPD (98 A1ATD). For A1ATD, 56.1% underwent single lung transplantation (80.6% for COPD). Early overall and complication-free survival was worse for A1ATD, but this trend reversed at longer follow up. Unadjusted estimated survival showed advantage for COPD at 90 days and 1 year, which attenuated by 5 years and reversed at 10 years (P<0.001). On adjusted analysis, A1ATD was associated with a trend toward lower complication-free survival at 90 days and 1 year, due partly to increased rates of post-transplant GI pathology, particularly in the era of the lung allocation score (LAS).

Conclusions

A1ATD lung recipients had worse short-term complication-free survival but improved long-term survival compared to COPD patients. A1ATD was associated with greater risk of new GI pathology after transplant. Close monitoring of A1ATD patients with timely evaluation of GI complaints after transplant is warranted.

Lung transplantation for chronic obstructive pulmonary disease: past, present, and future directions

PURPOSE OF REVIEW

Lung transplantation offers an effective treatment modality for patients with end-stage chronic obstructive pulmonary disease (COPD). The exact determination of when to refer, list, and offer transplant as well as the preferred transplant procedure type remains unclear. Additionally, there are special considerations specific to patients with COPD being considered for lung transplantation, including the implications of single lung transplantation on lung cancer risk, native lung hyperinflation, and overall survival.

RECENT FINDINGS

The International Society for Heart and Lung Transplantation's most recent recommendations rely on an assessment of COPD severity based on BODE index. Despite the lack of evidence supporting a mortality benefit of bilateral over single lung transplantation for COPD patients, the majority of transplants performed in this population remain bilateral. Some of the concerns specific to single lung transplantation remain the possibility of de novo native lung cancer and the hemodynamic and physiologic implications of acute native lung hyperinflation.

SUMMARY

COPD remains the most common worldwide indication for lung transplantation. Ongoing study is still required to assess the overall survival benefit of lung transplantation and assess the overall quality of life impact on the COPD patient population.

Advances in managing COPD related to α1 -antitrypsin deficiency: An under-recognized genetic disorder

α1 -Antitrypsin deficiency (AATD) predisposes individuals to chronic obstructive pulmonary disease (COPD) and liver disease. Despite being commonly described as rare, AATD is under-recognized, with less than 10% of cases identified. The following is a comprehensive review of AATD, primarily for physicians who treat COPD or asthma, covering the genetics, epidemiology, clinical presentation, screening and diagnosis, and treatments of AATD. For patients presenting with liver and/or lung disease, screening and diagnostic tests are the only methods to determine whether the disease is related to AATD. Screening guidelines have been established by organizations such as the World Health Organization, European Respiratory Society, and American Thoracic Society. High-risk groups, including individuals with COPD, nonresponsive asthma, bronchiectasis of unknown etiology, or unexplained liver disease, should be tested for AATD. Current treatment options include augmentation therapy with purified AAT for patients with deficient AAT levels and significant lung disease. Recent trial data suggest that lung tissue is preserved by augmentation therapy, and different dosing schedules are currently being investigated. Effective management of AATD and related diseases also includes aggressive avoidance of smoking and biomass burning, vaccinations, antibiotics, exercise, good diet, COPD medications, and serial assessment.

Transplant options for end stage chronic obstructive pulmonary disease in the context of multidisciplinary treatments

Lung transplantation (LTx) in advanced stage chronic obstructive pulmonary disease (COPD) patients is associated with significant improvement in lung function and exercise capacity. However, demonstration that the procedure also provides a survival benefit has been more elusive compared to other respiratory conditions. Identification of patients with increased risk of mortality is crucial: a low forced expiratory volume in 1 second (FEV₁) is perhaps the most common reason for referral to a lung transplant center, but in itself is insufficient to identify which COPD patients will benefit from LTx. Many variables have to be considered in the selection of candidates, time for listing, and choice of procedure: age, patient comorbidities, secondary pulmonary hypertension, the balance between individual and community benefit. This review will discuss patient selection, transplant listing, potential benefits and critical issues of bilateral (BLTx) and single lung (SLTx) procedure, donor-to-recipient organ size-matching; furthermore, it will describe LTx outcomes and its effects on recipient survival and quality of life.

Survival Benefit of Lung Transplantation in the Modern Era of Lung Allocation

RATIONALE

Lung transplantation is an accepted and increasingly employed treatment for advanced lung diseases, but the anticipated survival benefit of lung transplantation is poorly understood.

OBJECTIVES

To determine whether and for which patients lung transplantation confers a survival benefit in the modern era of U.S. lung allocation.

METHODS

Data on 13,040 adults listed for lung transplantation between May 2005 and September 2011 were obtained from the United Network for Organ Sharing. A structural nested accelerated failure time model was used to model the survival benefit of lung transplantation over time. The effects of patient, donor, and transplant center characteristics on the relative survival benefit of transplantation were examined.

MEASUREMENTS AND MAIN RESULTS

Overall, 73.8% of transplant recipients were predicted to achieve a 2-year survival benefit with lung transplantation. The survival benefit of transplantation varied by native disease group (P = 0.062), with 2-year expected benefit in 39.2 and 98.9% of transplants occurring in those with obstructive lung disease and cystic fibrosis, respectively, and by lung allocation score at the time of transplantation (P < 0.001), with net 2-year benefit in only 6.8% of transplants occurring for lung allocation score less than 32.5 and in 99.9% of transplants for lung allocation score exceeding 40.

CONCLUSIONS

A majority of adults undergoing transplantation experience a survival benefit, with the greatest potential benefit in those with higher lung allocation scores or restrictive native lung disease or cystic fibrosis. These results provide novel information to assess the expected benefit of lung transplantation at an individual level and to enhance lung allocation policy.

European Respiratory Society statement: diagnosis and treatment of pulmonary disease in α1-antitrypsin deficiency

α1-antitrypsin deficiency (AATD) is the most common hereditary disorder in adults. It is associated with an increased risk of developing pulmonary emphysema and liver disease. The pulmonary emphysema in AATD is strongly linked to smoking, but even a proportion of never-smokers develop progressive lung disease. A large proportion of individuals affected remain undiagnosed and therefore without access to appropriate care and treatment.

The most recent international statement on AATD was published by the American Thoracic Society and the European Respiratory Society in 2003. Since then there has been a continuous development of novel, more accurate and less expensive genetic diagnostic methods. Furthermore, new outcome parameters have been developed and validated for use in clinical trials and a new series of observational and randomised clinical trials have provided more evidence concerning the efficacy and safety of augmentation therapy, the only specific treatment available for the pulmonary disease associated with AATD.

As AATD is a rare disease, it is crucial to organise national and international registries and collect information prospectively about the natural history of the disease. Management of AATD patients must be supervised by national or regional expert centres and inequalities in access to therapies across Europe should be addressed.

Lung transplantation and survival outcomes in patients with oxygen-dependent COPD with regard to their alpha-1 antitrypsin deficiency status

Background

Individuals with severe alpha-1 antitrypsin deficiency (AATD) have an increased risk of developing COPD. However, outcomes during long-term oxygen therapy (LTOT) in patients with severe AATD and hypoxemia are unknown.

Patients and methods

This was a prospective, population-based, consecutive cohort study of patients on LTOT due to COPD in the period from January 1, 1987, to June 30, 2015, in the Swedish National Registry for Respiratory Failure (Swedevox). Severe AATD was identified using the Swedish AATD registry and confirmed by isoelectric focusing. Data on lung transplantation (LTx) were obtained from the two lung transplantation centers in Sweden. Mortality and causes of death were assessed based on the National Causes of Death Registry and analyzed using multivariable Cox regression.

Results

A total of 14,644 patients who started LTOT due to COPD were included in this study. No patient was lost to follow up. Patients with AATD were younger, included more males and more never smokers, and had fewer comorbidities. During a median follow-up of 1.6 years (interquartile range [IQR], 2.7) on LTOT, patients without severe AATD had a higher mortality, hazard ratio [HR] 1.53 (95% CI, 1.24–1.88), adjusting for age, sex, smoking status, body mass index, performance status, level of hypoxemia, and comorbidities. Cardiovascular deaths were increased. A higher proportion of AATD patients underwent LTx, 53 (19%) vs 118 (1%). Survival after LTx was similar for AATD and non-AATD patients and was predicted by age.

Conclusion

In oxygen-dependent COPD, patients with severe AATD have a longer survival time on LTOT, but they have a similar prognosis after lung transplantation compared with patients without AATD.

The important role of primary care providers in the detection of alpha-1 antitrypsin deficiency

OBJECTIVE

Alpha-1 antitrypsin deficiency (AATD) is an underrecognized genetic disorder that can cause chronic obstructive pulmonary disease (COPD) and liver cirrhosis, two clinical conditions commonly seen by primary care physicians. AATD is estimated to affect 1/4000-1/5000 people in the United States and 1-2% of all COPD cases.

METHODS

PubMed was searched for relevant articles using AAT/AATD-related terms.

RESULTS

Unfortunately, <10% of symptomatic individuals have been properly diagnosed primarily due to the underdiagnosis of COPD and the lack of awareness of AATD as a possible underlying cause. Because primary care providers are most likely to be the first to encounter symptomatic individuals, their role in the identification and early diagnosis of AATD patients is instrumental, particularly since therapy to slow lung disease progression is available. The diagnosis of AATD is laboratory-based rather than clinical. Testing for AATD should be part of the reflex testing that follows any COPD diagnosis or unexplained liver disease and can be performed by determining the AAT phenotype or genotype along with serum AAT levels. Both nonpharmacological and pharmacological approaches are recommended for treatment of lung disease, including smoking cessation, bronchodilators or supplemental oxygen as needed. Specific augmentation of AAT levels with regular purified AAT infusions has been found to slow lung function decline and emphysema progression in patients with moderate airflow obstruction and severely low serum AAT levels.

CONCLUSIONS

Improving primary care provider awareness and promoting regular reflex testing all COPD patients for AATD may significantly improve the care of COPD patients.

Survival after lung transplantation in recipients with alpha-1-antitrypsin deficiency compared to other forms of chronic obstructive pulmonary disease: a national cohort study

Alpha-1-antitrypsin deficiency (AATD) is grouped with chronic obstructive pulmonary disease (COPD); however, this may not be appropriate. This study assessed whether AATD confers a different prognosis than COPD following lung transplantation. We employed the United Network for Organ Sharing (UNOS) database, grouping patients by diagnoses of AATD or COPD. Kaplan-Meier methods and Cox modeling were performed to determine the association of diagnosis and overall survival. Of 9569 patients, 1394 (14.6%) had a diagnosis of AATD. Patients with AATD who received a single-lung transplant had reduced 1-year survival [adjusted hazard ratio (AHR): 1.68, 95% CI: 1.26, 2.23]. Among patients who received a bilateral lung transplant, there was no significant difference in survival by diagnosis (AHR for AATD as compared to COPD: 0.96, 95% CI: 0.82, 1.12). After the implementation of the lung allocation score (LAS), there was no significant difference in survival among patients who received a single (AHR: 1.15, 95% CI: 0.69, 1.95) or bilateral (AHR: 0.99, 95% CI: 0.73, 1.34) lung transplant by diagnosis. Lung transplantation is increasingly employed in the care of the patient with COPD. Although recipients undergoing LTX for AATD are at increased risk of both acute rejection and airway dehiscence post-transplant, in the post-LAS era, survival rates are similar for recipients with AATD in comparison with COPD.

Outcomes after lung transplantation

With more than 50,000 procedures having been performed worldwide, lung transplantation (LT) has become the standard of care for patients with end-stage chronic respiratory failure. LT leads to dramatic improvements in both pulmonary function and health related quality of life. Survival after LTs has steadily improved, but still lags far behind that observed after other solid organ transplantations, as evidenced by a median survival rate that currently stands at 5.8 years. Because of these disappointing results, the ability of LT to expand survival has been questioned. However, the most recent studies, based on sophisticated statistical modeling suggest that LT confers a survival benefit to the vast majority of lung transplant recipients. Chronic lung allograft dysfunction (CLAD) that develops in about 50% of recipients 5 years after LT is a major impediment to lung transplant survival. A better understanding of the mechanisms underlying CLAD could allow for better post-transplant survival.

Long-term clinical outcomes following treatment with alpha 1-proteinase inhibitor for COPD associated with alpha-1 antitrypsin deficiency: a look at the evidence

Alpha-1 antitrypsin deficiency (AATD) is a common hereditary disorder caused by mutations in the SERPINA1 gene, which encodes alpha-1 antitrypsin (AAT; also known as alpha 1-proteinase inhibitor, A₁-PI). An important function of A₁-PI in the lung is to inhibit neutrophil elastase, one of various proteolytic enzymes released by activated neutrophils during inflammation. Absence or deficiency of A₁-PI leads to an imbalance between elastase and anti-elastase activity, which results in progressive, irreversible destruction of lung tissue, and ultimately the development of chronic obstructive pulmonary disease with early-onset emphysema. AATD is under-diagnosed, patients can experience long delays before obtaining an accurate diagnosis, and the consequences of delayed diagnosis or misdiagnosis can be severe. Currently, A₁-PI therapy is the only available treatment that addresses disease etiology in patients with AATD; however, demonstrating clinical efficacy of A₁-PI therapy is challenging. In order to show therapeutic efficacy with traditional endpoints such as forced expiratory volume in one second and mortality, large sample sizes and longer duration trials are required. However, AATD is a rare, slow progressive disease, which can take decades to manifest clinically and recruiting sufficient numbers of patients into prolonged placebo-controlled trials remains a significant obstacle. Despite this, the Randomized, placebo-controlled trial of augmentation therapy in Alpha 1-Proteinase Inhibitor Deficiency (RAPID) and RAPID Extension trial, the largest clinical program completed to date, utilized quantitative chest computed tomography as a sensitive and specific measure of the extent of emphysema. Findings from the RAPID/RAPID Extension program definitively confirmed the benefits of A₁-PI therapy in slowing disease progression and provided evidence of a disease-modifying effect of A₁-PI therapy in patients with AATD. These findings suggest that the early introduction of treatment in patients with severe emphysema-related AATD may delay the time to death, lung transplantation or crippling respiratory complaints. In addition, there is now limited evidence that A₁-PI therapy provides a gain of more than five life-years, supporting previous observations based on registry data. With the clinical efficacy of A₁-PI therapy now demonstrated, further studies are required to assess long-term outcomes.

Treatment of lung disease in alpha-1 antitrypsin deficiency: a systematic review

BACKGROUND

Alpha-1 antitrypsin deficiency (AATD) is a rare genetic condition predisposing individuals to chronic obstructive pulmonary disease (COPD). The treatment is generally extrapolated from COPD unrelated to AATD; however, most COPD trials exclude AATD patients; thus, this study sought to systematically review AATD-specific literature to assist evidence-based patient management.

METHODS

Standard review methodology was used with meta-analysis and narrative synthesis (PROSPERO-CRD42015019354). Eligible studies were those of any treatment used in severe AATD. Randomized controlled trials (RCTs) were the primary focus; however, case series and uncontrolled studies were eligible. All studies had ≥10 participants receiving treatment or usual care, with baseline and follow-up data (>3 months). Risk of bias was assessed appropriately according to study methodology.

RESULTS

In all, 7,296 studies were retrieved from searches; 52 trials with 5,632 participants met the inclusion criteria, of which 26 studies involved alpha-1 antitrypsin augmentation and 17 concerned surgical treatments (largely transplantation). Studies were grouped into four management themes: COPD medical, COPD surgical, AATD specific, and other treatments. Computed tomography (CT) density, forced expiratory volume in 1 s, diffusing capacity of the lungs for carbon monoxide, health status, and exacerbation rates were frequently used as outcomes. Meta-analyses were only possible for RCTs of intravenous augmentation, which slowed progression of emphysema measured by CT density change, 0.79 g/L/year versus placebo (P=0.002), and associated with a small increase in exacerbations 0.29/year (P=0.02). Mortality following lung transplant was comparable between AATD- and non-AATD-related COPD. Surgical reduction of lung volume demonstrated inferior outcomes compared with non-AATD-related emphysema.

CONCLUSION

Intravenous augmentation remains the only disease-specific therapy in AATD and there is evidence that this slows decline in emphysema determined by CT density. There is paucity of data around other treatments in AATD. Treatments for usual COPD may not be as efficacious in AATD, and further studies may be required for this disease group.

Recent advances in understanding and treating COPD related to α1-antitrypsin deficiency

INTRODUCTION

Alpha-1-antitrypsin deficiency (AATD) is an orphan disease that predisposes individuals to COPD and liver disease. The following is a comprehensive review of AATD from epidemiology to treatment for physicians who treat COPD or asthma. Areas covered: In this comprehensive review of alpha-1-antitrypsin deficiency, we describe the historical perspective, genetics, epidemiology, clinical presentation and symptoms, screening and diagnosis, and treatments of the condition. Expert commentary: The two most important directions for advancing the understanding of AATD involve improving detection of the condition, especially in asymptomatic patients, and advancing knowledge of treatments directed specifically at AATD-related conditions. With regard to treatment for AATD-related conditions, research must continue to explore the implications and importance of augmentation therapy as well as consider new implementations that may prove more successful taking into consideration not only factors of pulmonary function and liver health, but also product availability and financial viability.

α1-Antitrypsin Deficiency

α1-Antitrypsin deficiency is an autosomal codominant condition that predisposes to emphysema and cirrhosis. The condition is common but grossly under-recognized. Identifying patients' α1-antitrypsin deficiency has important management implications (ie, smoking cessation, genetic and occupational counseling, and specific treatment with the infusion of pooled human plasma α1-antitrypsin). The weight of evidence suggests that augmentation therapy slows the progression of emphysema in individuals with severe α1-antitrypsin deficiency.

Enhancing Autophagy with Drugs or Lung-directed Gene Therapy Reverses the Pathological Effects of Respiratory Epithelial Cell Proteinopathy

Recent studies have shown that autophagy mitigates the pathological effects of proteinopathies in the liver, heart, and skeletal muscle but this has not been investigated for proteinopathies that affect the lung. This may be due at least in part to the lack of an animal model robust enough for spontaneous pathological effects from proteinopathies even though several rare proteinopathies, surfactant protein A and C deficiencies, cause severe pulmonary fibrosis. In this report we show that the PiZ mouse, transgenic for the common misfolded variant α1-antitrypsin Z, is a model of respiratory epithelial cell proteinopathy with spontaneous pulmonary fibrosis. Intracellular accumulation of misfolded α1-antitrypsin Z in respiratory epithelial cells of the PiZ model resulted in activation of autophagy, leukocyte infiltration, and spontaneous pulmonary fibrosis severe enough to elicit functional restrictive deficits. Treatment with autophagy enhancer drugs or lung-directed gene transfer of TFEB, a master transcriptional activator of the autophagolysosomal system, reversed these proteotoxic consequences. We conclude that this mouse is an excellent model of respiratory epithelial proteinopathy with spontaneous pulmonary fibrosis and that autophagy is an important endogenous proteostasis mechanism and an attractive target for therapy.

Lung Transplantation in Alpha-1-Antitrypsin Deficiency

BACKGROUND

Lung transplantation is a therapeutic option for patients with end-stage lung disease and a survival benefit has been described in patients with alpha-1-antitrypsin deficiency (A1ATD). The aims of the current study were to determine the survival and health benefits of lung transplantation in UK patients with A1ATD compared to carefully matched non-transplant patients.

METHODS

Patients with the PiZZ (alpha-1-antitrypsin deficiency) genotype who had undergone lung transplantation between 1996 and 2011 were identified from the UK A1ATD registry. Lung physiology, health status and survival were compared pre- and post-transplant using carefully matched non-transplant patients.

RESULTS

Thirty-two A1ATD patients who had undergone lung transplant were identified. Lung function decline pre-transplant was not different to the closely matched non-transplanted cohort. The transplant group pre-transplant, although matched for FEV1, had lower gas transfer measurements, (mean KCO% predicted 41.0% SE ± 3.86 vs 55.6% SE ± 3.10 p < 0.001) and worse health status (SGRQ mean score 64.2 SE ± 2.5 vs 55.3 SE ± 2.0, p < 0.001). Post-transplant, physiology and health status improved significantly (p < 0.002). However, the post-operative mortality over 5 years was no better than for a second group of non-transplant patients further matched for gas transfer or a third group also matched for SGRQ.

CONCLUSION

Patients who underwent lung transplant had lower gas transfer and quality-of-life pre-transplant compared to non-transplant patients matched for FEV1, age and sex, suggesting that these parameters provide extra information helpful in decision making. Lung transplantation for A1ATD patients significantly improves quality-of-life but not survival.

Augmentation therapy of alpha-1 antitrypsin deficiency associated emphysema

INTRODUCTION

Alpha-1 antitrypsin, secreted by the liver, inhibits neutrophil elastase. Its deficiency favours the development of emphysema. Restoring a "protective" serum level in deficient patients should make it possible to inhibit the development of emphysema.

STATE OF THE ART

Human plasma-derived alpha-1 antitrypsin is a blood-derived drug sold in France under the name Alfalastin(®). The recommended posology is an I.V. administration of 60 mg/kg once a week. Human plasma-derived alpha-1 antitrypsin restores anti-elastase protection in the lower lung and prevents experimental emphysema induced by the elastasis of human neutrophils in hamster. The low number of patients with alpha-1 antitrypsin deficiency is one of the difficulties to perform sufficiently powerful randomised studies. However, randomised studies have reported the efficacy of human plasma-derived alpha-1 antitrypsin perfusions on mortality, FEV1 decline and the frequency of exacerbations. Randomised control trials have demonstrated the efficacy of human plasma-derived alpha-1 antitrypsin perfusions on the loss of lung density assessed by CT scan.

CONCLUSION

Augmentation therapy is simple in its conception and implementation, but it is expensive. However, there are currently no other solutions.

Lung transplantation in chronic obstructive pulmonary disease: long-term survival, freedom from bronchiolitis obliterans syndrome, and factors influencing outcome

OBJECTIVES

Lung transplantation (LTx) remains the definitive treatment for end-stage lung failure, whereas chronic obstructive pulmonary disease (COPD) represents one of the main diagnoses leading to the indication for a transplant. We sought to assess long-term outcomes after LTx in patients diagnosed with COPD and analyze factors influencing outcome in this frequent patient cohort.

METHODS

Between January 2007 and November 2013, a total of 88 LTx were performed in patients with COPD in our institution. Patients with emphysema associated with alpha1-antitrypsin deficiency were excluded from this observation. The study design was a retrospective review of the prospectively collected data. A large number of pre-, intra-, and postoperative variables were analyzed including long-term survival and freedom from bronchiolitis obliterans syndrome (BOS). Furthermore, impact of different variables on survival was analyzed.

RESULTS

Preoperative donor data indicated a large proportion of marginal donors. While the overall cumulative survival after six yr was 57.4%, the results in terms of BOS-free survival in long-term follow-up were 39.7% after six yr. Patients with COPD were also associated with a low incidence (2.3%) of the need for postoperative extracorporeal life support (ECLS).

CONCLUSIONS

Long-term results after LTx in patients with COPD are acceptable with excellent survival, freedom from BOS, and low use of ECLS postoperatively despite permanently increasing proportion of marginal organs used.

Survival benefit of lung transplantation for chronic obstructive pulmonary disease in Sweden

BACKGROUND

Lung transplantation (LTx) is a therapeutic option for patients with life-threatening chronic obstructive pulmonary disease (COPD) that is refractory to conventional therapies. The survival benefit of LTx for COPD is difficult to assess. The aim of this study was to evaluate the Swedish series of LTx performed to treat COPD and to identify differences in outcome between COPD related to severe alpha-1-antitrypsin deficiency (AATD) and COPD with normal alpha-1-antitrypsin (AAT) levels.

METHODS

We retrospectively reviewed the data of 342 patients (128 AATD and 214 non-AATD) receiving lung transplants for end stage COPD from 1990 through 2012.

RESULTS

The majority (71%) of patients received a single lung transplant. The median survival time after LTx for all COPD patients was 9 years (95% confidence interval [CI]: 8 to 10). Non-AATD recipients had a shorter survival time than AATD recipients, 6 years (95% CI: 5.0 to 8.8) versus 12 years (95% CI: 9.6 to 13.5, p = 0.000). Mortality was higher among non-AATD recipients after adjusting for age, pack-years of smoking, body mass index, oxygen therapy use, exercise capacity, donor age, cytomegalovirus mismatch, and transplant type (hazard ratio 1.70, 95% CI: 1.02 to 2.82). The 5-year and 10-year survival rates for the AATD recipients were 75% and 59%, respectively, compared with 60% and 31% for the non-AATD recipients. Early deaths were mainly due to cardio/cerebrovascular accidents and sepsis, and late deaths to bronchiolitis obliterans syndrome and pulmonary infections.

CONCLUSIONS

Survival after LTx is significantly better for patients with severe AATD and end stage COPD than for the patients with COPD related to cigarette smoking.

Therapeutic targeting of misfolding and conformational change in α1-antitrypsin deficiency

Misfolding and conformational diseases are increasing in prominence and prevalence. Both misfolding and ‘postfolding’ conformational mechanisms can contribute to pathogenesis and can coexist. The different contexts of folding and native state behavior may have implications for the development of therapeutic strategies. α1-antitrypsin deficiency illustrates how these issues can be addressed with therapeutic approaches to rescue folding, ameliorate downstream consequences of aberrant polymerization and/or maintain physiological function. Small-molecule strategies have successfully targeted structural features of the native conformer. Recent developments include the capability to follow solution behavior of α1-antitrypsin in the context of disease mutations and interactions with drug-like compounds. Moreover, preclinical studies in cells and organisms support the potential of manipulating cellular response repertoires to process misfolded and polymer states.

Mysteries of α1-antitrypsin deficiency: emerging therapeutic strategies for a challenging disease

The classical form of α1-antitrypsin deficiency (ATD) is an autosomal co-dominant disorder that affects ~1 in 3000 live births and is an important genetic cause of lung and liver disease. The protein affected, α1-antitrypsin (AT), is predominantly derived from the liver and has the function of inhibiting neutrophil elastase and several other destructive neutrophil proteinases. The genetic defect is a point mutation that leads to misfolding of the mutant protein, which is referred to as α1-antitrypsin Z (ATZ). Because of its misfolding, ATZ is unable to efficiently traverse the secretory pathway. Accumulation of ATZ in the endoplasmic reticulum of liver cells has a gain-of-function proteotoxic effect on the liver, resulting in fibrosis, cirrhosis and/or hepatocellular carcinoma in some individuals. Moreover, because of reduced secretion, there is a lack of anti-proteinase activity in the lung, which allows neutrophil proteases to destroy the connective tissue matrix and cause chronic obstructive pulmonary disease (COPD) by loss of function. Wide variation in the incidence and severity of liver and lung disease among individuals with ATD has made this disease one of the most challenging of the rare genetic disorders to diagnose and treat. Other than cigarette smoking, which worsens COPD in ATD, genetic and environmental modifiers that determine this phenotypic variability are unknown. A limited number of therapeutic strategies are currently available, and liver transplantation is the only treatment for severe liver disease. Although replacement therapy with purified AT corrects the loss of anti-proteinase function, COPD progresses in a substantial number of individuals with ATD and some undergo lung transplantation. Nevertheless, advances in understanding the variability in clinical phenotype and in developing novel therapeutic concepts is beginning to address the major clinical challenges of this mysterious disorder.

A review of augmentation therapy for alpha-1 antitrypsin deficiency

INTRODUCTION

Alpha-1 antitrypsin deficiency (AATD) is a relatively common, but under-recognized condition which manifests commonly with liver cirrhosis and emphysema. Specific therapy for lung-affected individuals with AATD is augmentation therapy, which consists of intravenous infusion of purified human plasma-derived alpha-1 antitrypsin (AAT). Augmentation therapy was first approved by the United States Food and Drug Administration (FDA) in 1987 for emphysema associated with severe AATD and today, six augmentation therapy preparations, all of which derive from pooled human plasma, have received FDA approval.

AREAS COVERED

This paper reviews augmentation therapy for AATD, including the various available commercial preparations, their processing and biochemical differences, evidence regarding biochemical and clinical efficacy, patterns of clinical use, adverse effect profiles, cost-effectiveness and potential uses in conditions other than emphysema associated with AATD. Novel and emerging strategies for treating AATD are briefly discussed next, including alternative dosing and administration strategies, recombinant preparations, small molecule inhibitors of neutrophil elastase and of AAT polymerization, autophagy-enhancing drugs and gene therapy approaches.

EXPERT OPINION

We conclude with a discussion of our approach to managing patients with AATD and use of augmentation therapy.