All-trans retinoic acid results in irregular repair of septa and fails to inhibit proinflammatory macrophages.

All-trans retinoic acid (ATRA) is controversially discussed in emphysema therapy. We re-evaluated ATRA in the elastase model and hypothesised that beneficial effects should be reflected by increased alveolar surface area, elastin expression and downregulation of inflammatory mediators and matrix metalloproteinases (MMPs). Emphysema was induced by porcine pancreatic elastase versus saline in Sprague-Dawley rats. On days 26-37, rats received daily intraperitoneal injections with ATRA (500 µg · kg(-1) body weight) versus olive oil. Lungs were removed at day 38. Rat alveolar epithelial L2 cells were incubated with/without elastase followed by ATRA- or vehicle-treatment, respectively. ATRA only partially ameliorated structural defects. Alveolar walls exhibited irregular architecture: increased arithmetic mean thickness, reduction in surface coverage by alveolar epithelial cells type II. ATRA only partially restored reduced soluble elastin. It tended to increase the ratio of ED1(+):ED2(+) macrophages. Bronchoalveolar lavage (BAL) cells exhibited a proinflammatory state and high expression of interleukin-1ß, cytokine-induced neutrophil chemoattractant-1, tumour necrosis factor-α, nuclear factor-κB, MMP-2, MMP-9, MMP-12, tissue inhibitor of metalloproteinase (TIMP)-1 and TIMP-2 in emphysema, with ATRA exerting only few effects. MMP-7 was highly induced by ATRA in healthy but not in emphysematous lungs. ATRA reduced both MMP-2 and TIMP-1 activity in BAL fluid of emphysematous lungs. ATRA-therapy may bear the risk of unwanted side-effects on alveolar septal architecture in emphysematous lungs.

TNF-alpha-, TNF-beta-, IL-6-, and IL-10-promoter polymorphisms in patients with chronic obstructive pulmonary disease.

Chronic obstructive pulmonary disease (COPD) is a major health problem. The disease is driven by abnormal inflammatory reactions in response to inhaled particles and fumes. Therefore, inflammatory mediators are postulated to be of distinct importance. In the present case-control study, we investigated interleukin (IL)-promoter polymorphisms known to correlate with altered transcription levels of their gene products in patients with COPD. We analyzed tumor necrosis factor-alpha (TNF-alpha)-308, TNF-beta-intron1-252, IL-6-174, IL-10-819, and IL-10-1082 polymorphisms in 469 individuals using restriction fragment length polymorphism-based converted polymerase chain reaction. The study population consisted of 113 patients with COPD based on chronic bronchitis, divided into subgroups by severity (I degrees -III degrees ), 113 matched hospitalized individuals suffering from severe coronary heart disease without pulmonary disease (age-, sex-, and smoking-matched control group), and 243 healthy individuals (population control group). The matched analysis showed no significant differences in genotype distribution of all tested polymorphisms between the matched controls and the COPD patients. However, comparison with the population controls revealed significant differences in IL-10-1082 A/G genotype frequencies (P = 0.0247 for the whole COPD group, P = 0.009 for smokers only), with the genotypes carrying the G allele more common in the COPD cases [odds ratio (OR) = 1.66, 95% confidence interval (CI) 1.01-2.75; P = 0.046]. Interestingly, this shift toward more G alleles was even more pronounced in the matched control group (OR = 2.55, 95% CI 1.47-4.41; P = 0.0007), suggesting both presented groups share corresponding underlying mechanisms. The IL-10-1082_G allele is known to correlate with altered IL-10 levels. Therefore, it might be associated with altered or abnormal inflammatory response, a mechanism that could be postulated to be important in both chronic bronchitis and coronary heart disease.

Rare SP-A alleles and the SP-A1-6A(4) allele associate with risk for lung carcinoma.

Next to cigarette smoking, genetic factors may contribute to lung cancer risk. Pulmonary surfactant components may mediate response to inhaled carcinogenic substances and/or play a role in lung function and inflammation. We studied associations between surfactant protein (SP) genetic variants and risk in lung cancer subgroups. Samples (n=308) were genotyped for SP-A1, -A2, -B, and -D marker alleles. These included 99 patients with small cell lung carcinoma (SCLC, n=31), or non-SCLC (NSCLC, n=68) consisting of squamous cell carcinoma (SCC, n=35), and adenocarcinoma (AC) (n=23); controls (n=99) matched by age, sex, and smoking status (clinical control) to SCLC and NSCLC; and 110 healthy individuals (population control). We found (a) no significant marker associations with SCLC, (b) rare SP-A2 (1A9) and SP-A1 (6A11) alleles associate with NSCLC risk when compared with population control, (c) the same alleles (1A9, 6A11) associate with risk for AC when compared with population (6A11) or clinical control (1A9), and (d) the SP-A1-6A4 allele (found in approximately 10% of the population) associates with SCC, when compared with population or clinical control. A correlation between SP-A variants and lung cancer susceptibility appears to exist, indicating that SP-A alleles may be useful markers of lung cancer risk.

Surfactant protein B gene variations enhance susceptibility to squamous cell carcinoma of the lung in German patients.

Genetic factors are thought to influence the risk for lung cancer. Since pulmonary surfactant mediates the response to inhaled carcinogenic substances, candidate genes may be among those coding for pulmonary surfactant proteins. In the present matched case-control study a polymorphism within intron 4 of the gene coding for surfactant specific protein B was analysed in 357 individuals. They were divided into 117 patients with lung cancer (40 patients with small cell lung cancer, 77 patients with non small cell lung cancer), matched controls and 123 healthy individuals. Surfactant protein B gene variants were analysed using specific PCR and cloned surfactant protein B sequences as controls. The frequency of the intron 4 variation was similar in both control groups (13.0% and 9.4%), whereas it was increased in the small cell lung cancer group (17.5%) and the non small cell lung cancer group (16.9%). The gene variation was found significantly more frequently in patients with squamous cell carcinoma (25.0%, P=0.016, odds ratio=3.2, 95%CI=1.24-8.28) than in the controls. These results indicate an association of the surfactant protein B intron 4 variants and/or its flanking loci with mechanisms that may enhance lung cancer susceptibility, especially to squamous cell carcinoma of the lung.