Relationship Between α1-Antitrypsin Deficiency and Ascending Aortic Distention.

OBJECTIVE: To investigate the relationship between α1-antitrypsin deficiency (AATD), a disorder resulting in protease activity imbalances, and the risk of ascending aortic aneurysm. METHODS: In this single-center study, from August 1, 2018, to February 25, 2019, demographic data were retrospectively collated for patients with AATD-associated emphysema (AATD group) or non-AATD-associated emphysema (control group) with available high-resolution computed tomography scans. Mean ascending aortic diameter was compared between the groups, and the correlation of diameter with age was analyzed. RESULTS: Patients with AATD (n=51; mean AAT level, 20.3 mg/dL [to convert to µmol/L, multiply by 0.184]) were approximately 10 years younger than those in the control group (n=93; mean AAT level, 172.0 mg/dL), with a mean age of 55 vs 65 years. Overall and grouped by sex, the mean ascending aortic diameter in patients with AATD was not different from that in the control group (overall, 3.34 vs 3.37 cm; P=.68); however, ascending aortic diameter was significantly associated with age for patients in the AATD group (r=0.43; P=.0016), whereas no correlation was observed between age and aortic diameter in the control group (r=0.16; P=.11). CONCLUSION: Results of this study suggest that there is a pathologic association between AATD and aortic distention and that AATD may increase the risk of ascending aortic aneurysm. These data provide a basis for the regular assessment of aortic diameter in patients with AATD as well as for the testing of patients with aortic distention or aneurysm for AATD.

Clinical presentations of four patients with rare Alpha 1 Antitrypsin variants identified in a single US center.

Alpha 1 Antitrypsin Deficiency (AATD) is a rare condition primarily associated with lung complications and liver disease. As disease symptoms are similar to those in other respiratory conditions, patients generally experience long delays before receiving an accurate diagnosis and treatment. AATD results from mutations in the SERPINA1 gene that encodes Alpha 1 Antitrypsin (AAT). Over 500 single-nucleotide variants have been reported in mutation databases; however, there is increasing interest in the clinical significance of rare and novel SERPINA1 variants. In this case series of four patients from a single US center, next-generation sequencing (NGS) was used to guide AATD diagnosis. Four distinct rare variants of SERPINA1 (P289S; I50N; E204K; H262Y) were identified, three of which were found in patients with advanced chronic obstructive pulmonary disease (COPD)/emphysema. Computational modeling predicted these mutations to have potentially deleterious effects, a finding supported by AAT levels that were comparable with those seen in individuals heterozygous for the most common deficiency allele (PI*MZ). The remaining mutation (E204K) was found in a patient with a cerebral aneurysm; potential links between SERPINA1 variants and neurological conditions, such as cerebral aneurysm and arterial dissections, have been previously reported in individuals with heterozygous AATD phenotypes (PI*MS and PI*MZ). Novel and rare variants, often not detected by basic AATD diagnostic tests, have the potential to contribute to the development of COPD and emphysema. Detection of these variants can be enhanced by NGS, and modeling techniques can help determine if variants are pathogenic, thereby enabling a quicker, more accurate AATD diagnosis.

PredictAAT: Accounting for Inflammation in the Diagnosis of Alpha 1 Antitrypsin Deficiency.

Alpha 1 antitrypsin deficiency (AATD) is a rarely diagnosed hereditary condition characterized by low alpha 1 antitrypsin (AAT) levels, which can lead to early-onset emphysema due to accelerated degradation of lung tissue. Similar to C-reactive protein (CRP), AAT is an acute phase reactant, meaning that blood levels rise in response to inflammation, injury or infection. Testing AAT levels is essential in the diagnosis of AATD; however, the presence of inflammation at the time of AATD testing can provide a false 'normal' level reading of the patient's baseline AAT levels. Researchers from a US-wide screening program for AATD found that a large number of individuals with AATD variants (particularly with the PI*MZ genotype) presented with elevated CRP levels (≥5 mg/L), suggesting the presence of inflammation. Using a series of calculations, the relationship between AAT and CRP levels was characterized and found to be genotype specific. We have developed a publicly available, easy-to-use online calculator (PredictAAT) that enables the instant calculation of predicted baseline AAT levels in patients exhibiting elevated CRP levels that accounts for specific AATD genotype. There is a need to raise awareness of the importance of simultaneous determination of AAT and CRP levels to aid the accurate diagnosis of patients with AATD. The PredictAAT calculator is therefore a valuable tool for physicians to enhance early disease diagnosis and individualize treatment.

Protein modeling to assess the pathogenicity of rare variants of SERPINA1 in patients suspected of having Alpha 1 Antitrypsin Deficiency.

BACKGROUND: Alpha 1 Antitrypsin (AAT) is a key serum proteinase inhibitor encoded by SERPINA1. Sequence variants of the gene can cause Alpha 1 Antitrypsin Deficiency (AATD), a condition associated with lung and liver disease. The majority of AATD cases are caused by the 'Z' and 'S' variants - single-nucleotide variations (SNVs) that result in amino acid substitutions of E342K and E264V. However, SERPINA1 is highly polymorphic, with numerous potentially clinically relevant variants reported. Novel variants continue to be discovered, and without reports of pathogenicity, it can be difficult for clinicians to determine the best course of treatment. METHODS: We assessed the utility of next-generation sequencing (NGS) and predictive computational analysis to guide the diagnosis of patients suspected of having AATD. Blood samples on serum separator cards were submitted to the DNA1 Advanced Screening Program (Biocerna LLC, Fulton, Maryland, USA) by physicians whose patients were suspected of having AATD. Laboratory analyses included quantification of serum AAT levels, qualitative analysis by isoelectric focusing, and targeted genotyping and NGS of the SERPINA1 gene. Molecular modeling software UCSF Chimera (University College of San Francisco, CA) was used to visualize the positions of amino acid changes as a result of rare/novel SNVs. Predictive software was used to assess the potential pathogenicity of these variants; methods included a support vector machine (SVM) program, PolyPhen-2 (Harvard University, Cambridge, MA), and FoldX (Centre for Genomic Regulation, Barcelona, Spain). RESULTS: Samples from 23 patients were analyzed; 21 rare/novel sequence variants were identified by NGS, including splice variants (n = 2), base pair deletions (n = 1), stop codon insertions (n = 2), and SNVs (n = 16). Computational modeling of protein structures caused by the novel SNVs showed that 8 were probably deleterious, and two were possibly deleterious. For the majority of probably/possibly deleterious SNVs (I50N, P289S, M385T, M221T, D341V, V210E, P369H, V333M and A142D), the mechanism is probably via disruption of the packed hydrophobic core of AAT. Several deleterious variants occurred in combination with more common deficiency alleles, resulting in very low AAT levels. CONCLUSIONS: NGS and computational modeling are useful tools that can facilitate earlier, more precise diagnosis, and consideration for AAT therapy in AATD.

The Effects of Inflammation on Alpha 1 Antitrypsin Levels in a National Screening Cohort.

Alpha 1 Antitrypsin (AAT) is a highly polymorphic serum protein. Several genetic variants are associated with varying degrees of decreased serum levels; however, these levels can rise in response to infection, inflammation, injury and estrogen levels. Although the effect of inflammation is well established, it has never been studied quantitatively with respect to specific genotypes in a large representative sample. Using data from a national AAT deficiency-targeted screening cohort, we evaluated AAT levels of patients with normal and deficiency genotypes in response to inflammation, indicated by elevated serum C-reactive protein (CRP). Additionally, we utilized a regression analysis to adjust for the effect of inflammation for each genotype. Across all stratified genotype groups, increased AAT levels were observed in patients with CRP ≥5 mg/L. Different AAT phenotypes reacted differently in the acute phase; M showed a strong response and Z a reduced reaction. Nevertheless, we discovered that inflammation significantly masked clinically relevant base AAT levels in some PI*MZ individuals; approximately a quarter of PI*MZ samples showed signs of inflammation. Median AAT levels (mg/dL) in the presence of inflammation are given for several genotypes; numbers in parentheses are levels from the cohort without inflammation/adjusted levels from the cohort with inflammation using the newly devised algorithm: PI*MM: 162 (142/140); PI*MS: 136 (117/115); PI*MZ: 104 (85/89); PI*MF: 161 (132/141); PI*SS: 115 (96/91); PI*SZ: 66 (54/50). We conclude that simultaneous determinations of CRP and AAT levels, and genotyping are clinically valuable in defining AAT variants and that the effect of inflammation can be adjusted for.

State-of-the-art testing for alpha-1 antitrypsin deficiency.

BACKGROUND: Alpha-1 antitrypsin deficiency (AATD) is a genetic condition characterized by low serum levels of the protein alpha-1 antitrypsin. Because there are no unique clinical symptoms that point to a definitive diagnosis of AATD, laboratory testing is crucial to differentiate this disease from others. OBJECTIVE: To summarize advances in laboratory techniques used to test for AATD. METHODS: Data were sourced from a nonsystematic literature review of MEDLINE and the author's personal literature collection, and by checking reference lists of sourced articles. RESULTS: Since the original description of AATD by Laurell and Eriksson in 1963, testing methods have undergone major changes. Currently, alpha-1 antitrypsin protein is quantified by immunologic measurement in serum, and the phenotype is characterized by isoelectric focusing and/or targeted genotyping of predefined mutations. In addition, whole-gene sequencing of the gene SERPINA1 can be undertaken. However, this is costly and generally used only if targeted genotyping cannot conclusively identify the variant. The introduction of next-generation sequencing (NGS), which enables rapid and accurate sequencing of large quantities of DNA fragments in a single reaction, may help reduce costs. With its increasing availability, NGS may begin to appear in testing protocols. Clinical guidelines recommend that patients are tested for AATD if they have chronic irreversible airflow obstruction, especially those with early onset disease or a positive family history of AATD. Despite this, AATD is still underrecognized, and significant delays exist between symptom onset and diagnosis. CONCLUSION: Traditional testing practices have limitations. Screening programs that incorporate NGS are the most comprehensive methods available for accurate diagnosis of AATD.

Safety and pharmacokinetics of 120 mg/kg versus 60 mg/kg weekly intravenous infusions of alpha-1 proteinase inhibitor in alpha-1 antitrypsin deficiency: a multicenter, randomized, double-blind, crossover study (SPARK).

Augmentation therapy with the approved dose of 60 mg/kg weekly intravenous (IV) alpha-1 proteinase inhibitor (alpha1-PI), achieves a trough serum level of 11 µM in individuals with alpha-1 antitrypsin deficiency (AATD), yet this is still below the level observed in healthy individuals. This study assessed the safety and pharmacokinetic profile of weekly infusions of a 120 mg/kg dose of alpha1-PI in 30 adults with AATD. Subjects with symptomatic, genetically determined (genotypes PI*ZZ, PI*Z(null), PI*(null)(null) or PI*(Z)Mmalton) AATD were randomly assigned to weekly infusions of 60 or 120 mg/kg alpha1-PI (Prolastin-C®) for 8 weeks before crossing over to the alternate dose for 8 weeks. Adverse events (AEs) (including exacerbations), vital signs, pulmonary function tests, and laboratory assessments were recorded. Pharmacokinetic measurements included AUC0-7days, Cmax, trough, tmax, and t1/2, based on serum alpha1-PI concentrations. In total for both treatments, 112 AEs were reported, with exacerbation of COPD being the most frequent, consistent with the subjects' diagnoses. Mean steady-state serum alpha1-PI concentrations following 120 mg/kg weekly IV alpha1-PI were higher than with the 60 mg/kg dose and mean trough concentrations were 27.7 versus 17.3 µM, respectively. Dose proportionality was demonstrated for AUC0-7days and Cmax, with low inter-subject variability. The 120 mg/kg alpha1-PI weekly dose was considered to be safe and well tolerated, and provided more favorable physiologic alpha1-PI serum levels than the currently recommended 60 mg/kg dose. The effect of this dosing regimen on slowing and/or preventing emphysema progression in subjects with AATD warrants further investigation.

Elevated soluble HLA II protein levels in patients with alpha-1 antitrypsin deficiency with or without COPD.

Elevated levels of human leukocyte antigen (HLA) proteins have been reported in several pathologic conditions that are associated with increased concentrations of white blood cells (e.g., infection, inflammation, and lymphoproliferative disorders). The mechanisms by which HLA proteins are solubilized from cell membranes are insufficiently understood. We hypothesized that HLA proteins may be cleaved from cell membranes by insufficiently inhibited leukocytic elastase, as expected in alpha-1 antitrypsin deficiency (A1ATD), resulting in elevated plasma levels of soluble HLA (sHLA) proteins. Using an enzyme-linked immunosorbent assay, we measured sHLA II levels in the peripheral blood of patients with A1ATD with or without co-existing chronic obstructive pulmonary disease (COPD), with COPD only, and in a control group. Mean (±SD) sHLA II plasma levels were 110 ± 200 pg/mL in patients with A1ATD and COPD (Group 1), 10 ± 30 pg/mL in patients with COPD without A1ATD (Group 2), 70 ± 90 pg/mL in patients with A1ATD without COPD (Group 3), and 10 ± 30 pg/mL in healthy donors (Group 4). Soluble HLA II plasma levels were significantly higher in Group 1 (P = .001) and Group 3 (P = .002) versus Group 4. Our preliminary results suggest that leukocytic elastase and probably other proteinases solubilize HLA proteins from cell membranes. This mechanism would operate in inflammation with elevated leukocytic elastase levels but more so with inflammation and A1ATD, where elastase would be insufficiently inhibited. If this mechanism is verified, plasma sHLA levels could potentially be used to measure cell damage due to proteinases and, therefore, for monitoring the therapeutic efficacy of alpha-1 antitrypsin (A1AT) augmentation therapy.

Pharmacokinetic comparability of Prolastin®-C to Prolastin® in alpha1-antitrypsin deficiency: a randomized study.

BACKGROUND: Alpha1-antitrypsin (AAT) deficiency is characterized by low blood levels of alpha1-proteinase inhibitor (alpha1-PI) and may lead to emphysema. Alpha1-PI protects pulmonary tissue from damage caused by the action of proteolytic enzymes. Augmentation therapy with Prolastin® (Alpha1-Proteinase Inhibitor [Human]) to increase the levels of alpha1-PI has been used to treat individuals with AAT deficiency for over 20 years. Modifications to the Prolastin manufacturing process, incorporating additional purification and pathogen-reduction steps, have led to the development of an alpha1-PI product, designated Prolastin®-C (Alpha1-Proteinase inhibitor [Human]). The pharmacokinetic comparability of Prolastin-C to Prolastin was assessed in subjects with AAT deficiency. METHODS: In total, 24 subjects were randomized to receive 60 mg/kg of functionally active Prolastin-C or Prolastin by weekly intravenous infusion for 8 weeks before crossover to the alternate treatment for another 8 weeks. Pharmacokinetic plasma samples were drawn over 7 days following last dose in the first treatment period and over 10 days following the last dose in the second period. The primary end point for pharmacokinetic comparability was area under the plasma concentration versus time curve over 7 days post dose (AUC0₋7 (days)) of alpha1-PI determined by potency (functional activity) assay. The crossover phase was followed by an 8-week open-label treatment phase with Prolastin-C only. RESULTS: Mean AUC0₋7 (days) was 155.9 versus 152.4 mg*h/mL for Prolastin-C and Prolastin, respectively. The geometric least squares mean ratio of AUC0₋7 (days) for Prolastin-C versus Prolastin had a point estimate of 1.03 and a 90% confidence interval of 0.97-1.09, demonstrating pharmacokinetic equivalence between the 2 products. Adverse events were similar for both treatments and occurred at a rate of 0.117 and 0.078 per infusion for Prolastin-C (double-blind treatment phase only) and Prolastin, respectively (p = 0.744). There were no treatment-emergent viral infections in any subject for human immunodeficiency virus, hepatitis B or C, or parvovirus B19 during the course of the study. CONCLUSION: Prolastin-C demonstrated pharmacokinetic equivalence and a comparable safety profile to Prolastin. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT00295061.

Lateral-horizontal patient position and horizontal orientation of the endotracheal tube to prevent aspiration in adult surgical intensive care unit patients: a feasibility study.

BACKGROUND: Recent data suggest that during mechanical ventilation the lateral-horizontal patient position (in which the endotracheal tube is horizontal) decreases the risk of ventilator-associated pneumonia, compared to the recommended semi-recumbent position (in which the endotracheal tube slopes downward into the trachea). We tested the feasibility of the lateral-horizontal patient position, measured the incidence of aspiration of gastric contents, and watched for any adverse effects related to the lateral-horizontal position. METHODS: Ten adult intensive care unit patients were ventilated for 64 hours in the standard semi-recumbent position, and ten for 12-24 hours in the lateral-horizontal position. Tracheal secretions were collected every 8 hours and every 4 hours, respectively, and tested for pepsin, which is a marker of gastric contents. We also recorded clinical, physiologic, and outcome variables. RESULTS: The patients remained stable during ventilation in the lateral-horizontal position, and no adverse events occurred. Pepsin was detected in the trachea of 7 semi-recumbent patients and in five of the lateral-horizontal patients (P = .32). The number of ventilator-free days was 8 days (range 0-21 days) in the semi-recumbent patients, versus 24 days (range 12-25 days) in the lateral-horizontal patients (P = .04). CONCLUSIONS: Implementing the lateral-horizontal position for 12-24 hours in adult intubated intensive care unit patients is feasible, and our patients had no adverse events. The incidence of aspiration of gastric contents in the lateral-horizontal position seems to be similar to that in the semi-recumbent position.

Multi-center study: the biochemical efficacy, safety and tolerability of a new alpha1-proteinase inhibitor, Zemaira.

Augmentation therapy with a plasma derived alpha l-Proteinase Inhibitor (alpha1 -PI) has been demonstrated to be effective in restoring serum Alpha1 -antitrypsin (AAT)* levels in individuals with AAT Deficiency (note: alpha1 PI and AAT are synonymous). The objective of this study was to demonstrate that the steady-state trough serum alphal-PI levels, achieved by a new plasma derived alpha,-PI (Zemaira, study drug, ZLB Behring LLC, King of Prussia, Pennsylvania, USA), were bioequivalent to those achieved by the currently available alpha-PI therapy, Prolastin (control drug, Bayer Corporation, Berkeley, California, USA), and maintained weekly trough serum antigenic alpha1-PI levels above the protective threshold of 11 microM. This multi-center, controlled study randomized a total of 44 subjects to receive either study or control drug for a 10-week double-blind phase. The control group was then crossed over to receive the study drug for the remainder of the study (14 weeks). The difference in mean trough serum antigenic alpha1-PI level between the treatment groups was 1.45 microM (90% CI-2.77, -0.13), signifying bioequivalence. The mean trough serum antigenic alpha1-PI level in the study drug group was greater than the therapeutic threshold of 11 microM, achieving a level of 17.7 microM during the steady-state period. Treatment-related adverse events (AEs) were seen in 7% and 21% of study and control drug treated subjects, respectively. No documented viral transmission occurred. These results demonstrate that the new plasma derived alpha1-PI (Zemaira) is bioequivalent to the currently available product Prolastin, is well tolerated, and safe with respect to the risk of viral transmission.

Aspiration of gastric contents: association with prehospital intubation.

We prospectively compared the incidence of pulmonary aspiration of gastric contents between patients endotracheally intubated in the prehospital (PH) setting and those intubated in the emergency department (ED). Tracheal aspirates were collected using a standard Leukens trap from all patients as soon as possible after endotracheal intubation. Tracheal aspirates were then tested for the presence of pepsin, a sensitive and specific marker of gastric contents, using a fibrinogen digestion technique. Over 8 months, 168 patients were enrolled. The pepsin assay was positive in 10 of 20 (50%) patients intubated in the PH group, as opposed to 33 of 148 (22%) of those intubated in the ED (chi2 P=.008; odds ratio, 3.5; 95% CI, 1.34-9.08). Patients endotracheally intubated in the PH setting are more likely to have aspirated gastric contents than those intubated in the ED.

Severe, early-onset emphysema with normal alphal-antitrypsin levels in nonsmokers: a clinical dilemma.

Approximately 85% of all cases of chronic obstructive pulmonary disease are attributed to cigarette smoking. The only other established risk factor for the development of chronic obstructive pulmonary disease that is of comparable importance is the deficiency of alpha1-antitrypsin, a rare genetic defect that is present in less than 1% of all cases. Other risk factors are not well characterized in the literature. This article describes one patient without a significant smoking history and with a normal alphaa-antitrypsin level who developed severe early-onset emphysema and gives a brief discussion about other genetic and environmental risk factors for the development of emphysema.

A new pepsin assay to detect pulmonary aspiration of gastric contents among newly intubated patients.

Aspiration of gastric contents by endotracheally intubated patients is associated with significant morbidity and mortality. Previous studies suggest that pepsin in tracheal aspirates may be a valuable marker of occult aspiration. We sought to show the sensitivity and specificity of a new, pepsin-specific assay in humans. A prospective, case-controlled study was conducted with subjects serving as their own controls. After planned endotracheal and nasogastric intubation for elective surgery, 20 participants had tracheal and gastric aspirates withdrawn. A blinded investigator tested samples for the presence of pepsin using the assay. Positive samples were then tested with pepstatin, a specific pepsin inhibitor, to ensure that positive results were due to pepsin. All tracheal aspirates tested negative and all gastric aspirates tested positive for pepsin. Pepstatin halted pepsin activity in all positive samples, ensuring that positive results were due to pepsin. A pepsin-specific assay is extremely reliable for detecting gastric contents in humans.

Comparison of a salivary/sputum pepsin assay with 24-hour esophageal pH monitoring for detection of gastric reflux into the proximal esophagus, oropharynx, and lung.

The purpose of this study was to determine whether measurement of salivary/sputum pepsin could be used as a surrogate marker for detecting gastroesophageal reflux using 24-hr esophageal pH monitoring as the gold standard. Patients with gastroesophageal reflux symptoms underwent simultaneous 24-hr esophageal pH monitoring and collection of saliva and sputum samples for pepsin measurement using a recently developed assay. In all, 16 patients provided 19 positive (10.6%) and 161 negative pepsin assays. The mean pH values for the positive pepsin samples were lower then the negative samples at both the proximal [5.34 (95% CI, 4.94-5.75) vs 6.12 (95% CI, 6.03-6.20; P < 0.01)] and distal [4.97 (95% CI, 4.61-5.33) vs 6.03 (95% CI, 5.92-6.15; P < 0.01)] pH probes. Proximal esophageal reflux was not detected in patients who had a negative pepsin assay (N = 12); in contrast, proximal esophageal reflux was documented in three of four patients with a positive assay. In conclusion, detection of pepsin in the saliva and/or sputum may provide a noninvasive method to test for the proximal reflux of gastric contents.