Tumour necrosis factor family genes in a phenotype of COPD associated with emphysema.

Genetic factors are believed to play a role in the individual susceptibility to chronic obstructive pulmonary disease (COPD). Tumour necrosis factor (TNF) family genes have been widely investigated but inconsistent results may lie either in the genetic heterogeneity of populations or in the poor phenotype definition. A genetic study was performed using a narrower phenotype of COPD. The authors studied 86 healthy smokers and 63 COPD subjects who were enrolled based on irreversible airflow obstruction (forced expiratory volume in one second/forced vital capacity <70% predicted) and a diffusing capacity for carbon monoxide <50% predicted (moderate-to-severe COPD associated with pulmonary emphysema). The following polymorphisms were investigated: TNF-308, the biallelic polymorphism located in the first intron of the lymphotoxin-alpha gene, and exon 1 and exon 6 of the TNF receptor 1 and 2 genes, respectively. No significant deviations were found concerning the four polymorphisms studied between the two populations. The authors confirm that the tumour necrosis factor family genes, at least for the polymorphisms investigated, are not major genetic risk factors for chronic obstructive pulmonary disease in Caucasians, either defined in terms of emphysema (this study) or airflow obstruction (previous studies). Nevertheless, the authors would like to emphasise the importance of narrowing the phenotype in the search for genetic risk factors in chronic obstructive pulmonary disease.

Endogenous nitric oxide in patients with chronic heart failure (CHF): relation to functional impairment and nitrate-containing therapies.

We assessed the levels of exhaled nitric oxide (eNO) in patients with chronic heart failure (CHF) according to the functional impairment and the use of nitrate-containing agents. Forty patients (age 55+/-9 years) were classified according to the NYHA classes I-II (n=18, group 1) and classes III-IV (n=22, group 2), and to the use of nitrate-containing drugs (Nitrate+, Nitrate-). Twenty-two healthy age-related subjects served as controls (group 3). Respiratory function, symptom-limited incremental cycloergometry and resting eNO concentration at peak (FENOp) or plateau (FENOpl) of the single-breath exhalation curve were assessed in all subjects. FENOpl was significantly lower in patients than in controls (7.8+/-2.7 and 10.6+/-2.8 ppb, respectively, P<0.005) and lower in most severe CHF patients (7.1+/-2.6 and 8.8+/-2.7 ppb in group 2 and group 1, respectively, P<0.05). A significant correlation between peak V'O(2), Watts and FENOpl (r=0.42, P<0.013 and r=0.46, P=0.008, respectively) was found. Independent of NYHA class, Nitrate+ showed higher FENOp levels than Nitrate- patients (36.9+/-15.7 vs. 28. 1+/-15.1 ppb, P<0.05). Resting eNO was lower in the most compromised CHF patients and was significantly related to exercise capacity. Nitrate-containing agents might influence the levels of eNO in these patients.

Tumor necrosis factor gene complex in COPD and disseminated bronchiectasis.

BACKGROUND: Tumor necrosis factor (TNF) is a potent proinflammatory cytokine with increased levels in the sputum of COPD subjects. Two biallelic TNF gene complex polymorphisms have been described: LtalphaNcoI, in the first intron of the lymphotoxin alpha (previously referred to as TNF-beta) gene, and TNF-308, in the promoter region of the TNF-alpha gene. Higher levels of TNF production are associated with allele 1 of LtalphaNcoI (LtalphaNcoI*1) and with allele 2 of TNF-308 (TNF-308*2). STUDY OBJECTIVES: To study the frequencies of the two TNF gene complex polymorphisms in patients with COPD and bronchiectasis. DESIGN: Association study. SUBJECTS AND METHODS: We studied the frequencies of these polymorphisms in 66 subjects with COPD and in 23 subjects with disseminated bronchiectasis and compared them to the frequencies in 98 healthy control subjects and 45 subjects with nonobstructive pulmonary disease. Genomic DNA samples were extracted, and TNF-alpha and LtalphaNcoI polymorphisms were detected after polymerase chain reaction by restriction digestion. RESULTS: We found the following frequencies: the TNF-308*2 allele was detected in 11% of COPD individuals, 15% of bronchiectasis patients, 10% of healthy control subjects, and 18% of subjects with nonobstructive pulmonary disease. The LtalphaNcoI*1 allele was detected in 28% of COPD individuals, 30% of bronchiectasis patients, 29% of healthy control subjects, and 29% of subjects with nonobstructive pulmonary disease. We found evidence of linkage disequilibrium between the two loci (Delta = 0.068). CONCLUSIONS: We conclude that the TNF gene complex, at least in Caucasoid individuals and for the considered polymorphisms, does not seem to play a major role as genetic risk factor in COPD and bronchiectasis.

alpha 1-antitrypsin TAQ I polymorphism and alpha 1-antichymotrypsin mutations in patients with obstructive pulmonary disease.

Obstructive pulmonary disease is a multifactorial condition deriving from the interaction of environmental and genetic factors. From biochemical knowledge of the basis of the disease, alpha 1-antitrypsin and alpha 1-antichymotrypsin are considered two likely candidate genes. We therefore designed an association study comprising 232 unrelated Italian individuals divided as follows: 89 individuals with obstructive lung disease (66 with COPD and 23 with disseminated bronchiectasis) and 143 controls (45 patients with non-obstructive lung disease and 98 healthy individuals). We screened for Taq I (G1237A) polymorphism of the alpha 1-antitrypsin gene as well as the rare variants Bonn-1 (Pro229Ala), Bochum-1 (Leu55Pro), Isehara-1 (Met389Val) and Isehara-2 (1258delAA), and the common signal peptide polymorphism Thr-15Ala of the alpha 1-antichymotrypsin gene. The frequencies of Taq I G1237A alleles were 11.7 and 10.8% in obstructed patients and controls, respectively (P = 0.43), while those of signal peptide Thr-15Ala alleles were 51.6 and 50.3% in obstructed patients and controls, respectively (P = 0.42). We conclude that alpha 1-antitrypsin Taq I polymorphism and alpha 1-antichymotrypsin Thr-15Ala mutation are not major genetic risk factors for the development of obstructive lung disease in Italian patients. The alpha 1-antichymotrypsin rare variants were not detected: our results do not exclude the possibility that other alpha 1-antichymotrypsin gene mutations might be present in Italian obstructed patients but, if so, these genetic defects must be rare.

Complete mutational screening of the CFTR gene in 120 patients with pulmonary disease.

In order to determine the possible role of the cystic fibrosis transmembrane regulator (CFTR) gene in pulmonary diseases not due to cystic fibrosis, a complete screening of the CFTR gene was performed in 120 Italian patients with disseminated bronchiectasis of unknown cause (DBE), chronic bronchitis (CB), pulmonary emphysema (E), lung cancer (LC), sarcoidosis (S) and other forms of pulmonary disease. The 27 exons of the CFTR gene and their intronic flanking regions were analyzed by denaturing gradient gel electrophoresis and automatic sequencing. Mutations were detected in 11/23 DBE (P = 0.009), 7/25 E, 5/27 CB, 5/26 LC, 5/8 S (P = 0.013), 1/4 tuberculosis, and 1/5 pneumonia patients, and in 5/33 controls. Moreover, the IVS8-5T allele was detected in 6/25 E patients (P = 0.038). Four new mutations were identified: D651N, 2377C/T, E826K, and P1072L. These results confirm the involvement of the CFTR gene in disseminated bronchiectasis of unknown origin, and suggest a possible role for CFTR gene mutations in sarcoidosis, and for the 5T allele in pulmonary emphysema.

Serum type I and type III procollagen peptide levels in sarcoidosis.

Type I and type III are the most abundant collagens in the lung. The aim of our study was to compare type I and III procollagen peptides in sera of sarcoid patients. Sixty eight patients with sarcoidosis were studied (19 with newly recognized disease, 7 with relapsing disease, 15 with chronic disease, and 27 in stable remission). Thirty healthy volunteers served as controls. The levels of procollagen I and III peptides were determined by radioimmunoassay. Angiotensin-converting enzyme (ACE) level was evaluated by means of a colorimetric assay. In patients with newly recognized sarcoidosis, both serum procollagen I and III peptide levels were increased with respect to controls (p=0.0014 and p<0.00001, respectively). There was a poor correlation between levels of procollagen I and III (r=0.26), whereas there was a closer correlation between procollagen III and ACE (r=0.69). Procollagen I peptide level did not identify patients in roentgenological stage III. In conclusion, in patients with newly recognized sarcoidosis there is a significant increase in the serum level of procollagen I peptide. However, procollagen I peptide is not a marker of sarcoid patients with fibrosis, ie. stage III disease. Its clinical usefulness seems to be weaker than that of procollagen III peptide.