Alpha1-antitrypsin deficiency in Greece: Focus on rare variants.

PURPOSE: A1Antitrypsin deficiency (AATD) pathogenic mutations are expanding beyond the PI*Z and PI*S to a multitude of rare variants. AIM: to investigate genotype and clinical profile of Greeks with AATD. METHODS: Symptomatic adult-patients with early-emphysema defined by fixed airway obstruction and computerized-tomography scan and lower than normal serum AAT levels were enrolled from reference centers all over Greece. Samples were analyzed in the AAT Laboratory, University of Marburg-Germany. RESULTS: Included are 45 adults, 38 homozygous or compound heterozygous for pathogenic variants and 7 heterozygous. Homozygous were 57.9% male, 65.8% ever-smokers, median (IQR) age 49.0(42.5-58.5) years, AAT-levels 0.20(0.08-0.26) g/L, FEV1(%predicted) 41.5(28.8-64.5). PI*Z, PI*Q0, and rare deficient allele's frequency was 51.3%, 32.9%,15.8%, respectively. PI*ZZ genotype was 36.8%, PI*Q0Q0 21.1%, PI*MdeficientMdeficient 7.9%, PI*ZQ0 18.4%, PI*Q0Mdeficient 5.3% and PI*Zrare-deficient 10.5%. Genotyping by Luminex detected: p.(Pro393Leu) associated with MHeerlen (M1Ala/M1Val); p.(Leu65Pro) with MProcida; p.(Lys241Ter) with Q0Bellingham; p.(Leu377Phefs*24) with Q0Mattawa (M1Val) and Q0Ourem (M3); p.(Phe76del) with MMalton (M2), MPalermo (M1Val), MNichinan (V) and Q0LaPalma (S); p.(Asp280Val) with PLowell (M1Val); PDuarte (M4), YBarcelona (p.Pro39His). Gene-sequencing (46.7%) detected Q0GraniteFalls, Q0Saint-Etienne, Q0Amersfoort(M1Ala), MWürzburg, NHartfordcity and one novel-variant (c.1A>G) named Q0Attikon.Heterozygous included PI*MQ0Amersfoort(M1Ala), PI*MMProcida, PI*Mp.(Asp280Val), PI*MOFeyzin. AAT-levels were significantly different between genotypes (p = 0.002). CONCLUSION: Genotyping AATD in Greece, a multiplicity of rare variants and a diversity of rare combinations, including unique ones were observed in two thirds of patients, expanding knowledge regarding European geographical trend in rare variants. Gene sequencing was necessary for genetic diagnosis. In the future the detection of rare genotypes may add to personalize preventive and therapeutic measures.

Prevalence of pulmonary hypertension in patients with idiopathic pulmonary fibrosis: correlation with physiological parameters.

The aim of this study was to prospectively evaluate the prevalence of pulmonary hypertension (PH) in patients with idiopathic pulmonary fibrosis (IPF). One hundred thirty-nine patients (101 male, mean age = 68.6 ± 9 years), with confirmed IPF and who were admitted to eight Pulmonary Departments in Greece between November 2005 and December 2006 were included in the study. Pulmonary artery systolic pressure (PASP) was estimated by echocardiography, and PH was defined as PASP > 36 mmHg. We compared demographics, pulmonary function tests, NYHA functional status, 6-min walk distance (6MWD), B-type natriuretic peptide (BNP), PaO(2), and P(A-a)O(2) at rest data between patients with PH and without PH (PASP ≤ 36 mmHg). Increased estimated right ventricular systolic pressure was present in 55% of patients (mean PASP = 47.1 ± 11.2 mmHg vs. 30.3 ± 3.8 mmHg, respectively). Patients with PH had a lower but not statistically significant DL(CO) (47.1 ± 18.8 vs. 52.5 ± 20.1), lower PaO(2) at rest (64.6 ± 12.2 vs. 71.1 ± 11.3, P = 0.004), and lower mean 6MWD (282 ± 118 vs. 338 ± 91, P = 0.007). Significant differences were also observed in the NYHA functional status between the two groups (P = 0.02). Statistically significant correlations were observed between PASP and PaO(2) at rest (r = -0.331, P = 0.00), P(A-a)O(2) at rest (r = 0.494, P = 0.00)(,) 6MWD (r = -0.264, P = 0.01), SpO(2) at rest (r = -0.293, P = 0.00), SpO(2) at the end of exercise (r = -0.364, P = 0.00), and also BNP values (r = 0.319, P = 0.01). Moreover, PaO(2) (P = 0.02), P(A-a)O(2) (P = 0.005), and SpO(2) at the end of exercise (P = 0.023) were independent predictors of the presence of estimated PH. Using Doppler echocardiography as a screening tool for the estimation of PH, we found that PH is common in patients with IPF. Gas exchange parameters at rest and exercise desaturation might indicate underlying PH in IPF.

Hering-Breuer reflex in normal adults and in patients with chronic obstructive pulmonary disease and interstitial fibrosis.

BACKGROUND: It has been suggested that the Hering-Breuer reflex (HBR) is unimportant in adults during normal tidal breathing and that it is elicited only if tidal volume is increased above a certain critical threshold. OBJECTIVE: The aim of this study was (1) to study the occurrence of the HBR in adults with normal pulmonary function and (2) to examine if changes in lung mechanics have any effect on the HBR. METHODS: We examined 11 adults with normal pulmonary function, 8 patients with chronic destructive pulmonary disease (COPD) and 3 with interstitial fibrosis (IF). All subjects were lightly sedated with fentanyl, intubated and ventilated with a Servo-900 ventilator. Inspiratory and expiratory flow (and after integration, volume) and mouth pressure were recorded from the endotracheal tube with a pneumotachograph and a pressure transducer. Pressure support ventilation was applied in all patients and functional residual capacity (FRC) was measured with the N(2) washout method. Mean (Te(mean)) and maximal expiratory time (Te(max)) were determined for each individual for 20 breaths. Following several breaths to establish a stable baseline the airway was occluded at end inspiration by a shutter. A positive HBR was interpreted as longer Te(occ) than Te(max) (Te(occ)/Te(max), %). Occlusion was maintained until negative airway pressure occurred and the occlusion time (Te(occ)) was measured. We attempted occlusions after the addition of 5 cm H2O positive end-expiratory pressure (PEEP) and subsequently with 10, 15 and 20 cm H(2)O PEEP. Te(occ) was measured of progressively larger lung volumes. To examine the HBR sensitivity in the three groups, we plotted the lung volumes of occlusion against the corresponding Te(occ)/Te(max). RESULTS: The ratio Te(occ)/Te(max) increased from 167.5 +/- 82.5 at normal FRC to 474 +/- 200.2 s (PEEP(20)). On the contrary, in patients with COPD, Te(occ)/Te(max) increased from 125.2 +/- 34 to 193.7 +/- 74.2 (p < 0.05). CONCLUSIONS: The HBR was positive in all subjects. COPD patients were found to be less sensitive to volume changes when compared with normal controls and with IF patients.