Progressive pulmonary emphysema associated with congenital generalized elastolysis (cutis laxa)

Aortic root dilatation in patients with emphysema

BACKGROUND

Abdominal aortic aneurysms have been recognized to occur more frequently in patients with emphysema. However, the prevalence of aortic root dilatation in patients with emphysema and its relationship to risk factors for aortic enlargement have not been previously described.

METHODS

We studied 47 patients, past smokers (aged 67 +/- 6 years, 18 women) with severe emphysema diagnosed by a pulmonary function test and an ultrafast computed tomographic scan. Two-dimensional echocardiography was used to measure the aortic root at the aortic annulus, sinus of Valsalva, sinotubular junction and proximal part of the ascending aorta. Measured mean values were compared with published normal values and age- and sex-matched patients without emphysema. The relationship between aortic root size and cardiac risk factors (hypertension, hypercholesterolemia, and diabetes) was also examined.

RESULTS

In patients with emphysema the mean aortic root dimensions were significantly larger than normal values at each measured site (P <.0001) and those of patients without emphysema (P <.05 to.0001). A substantial percentage of patients with emphysema had larger sinus of Valsalva (43%) and proximal ascending aorta (59%) than the upper limit of normal. In the multivariable regression model, emphysema was a significant determinant of aortic root size at all measured sites and hypertension was associated with additional dilatation at the sinus of Valsalva, sinotubular junction, and proximal ascending aorta.

CONCLUSIONS

(1) In patients with emphysema the aortic root dimension is significantly larger than in patients without emphysema. (2) Systemic hypertension is associated with additional enlargement of the proximal ascending aorta, the sinus of Valsalva, and the sinotubular junction.

Proteinase imbalance versus biomechanical stress in pulmonary emphysema

Emphysema is a slowly progressive degenerative lung disease involving fragmentation and depletion of elastic fibers, loss of lung elastance, and architectural destruction with ectasia, tortuosity, and loss of bronchioles irrespective of localization or morphological type. Occurring under physiological conditions, predominantly in geriatrics, matrix laxity and destructive parenchymal lesions are indicative of a pathological loss of tissue tensile strength attributable to bioengineering or structural fatigue in repetitively stressed tissues. The occurrence of severe premature emphysema in inherited connective tissue diseases and under some experimental and iatrogenic conditions is supportive evidence. Experiments advocating unrestrained proteolysis as a cause or pathogenic factor are invalid, being based on a false premise and assumed causality.

Genes, oxidative stress, and the risk of chronic obstructive pulmonary disease

BACKGROUND

The first-pass metabolism of foreign compounds in the lung is an important protective mechanism against oxidative stress. We investigated whether polymorphisms in the gene for microsomal epoxide hydrolase (mEPHX), an enzyme involved in this protective process, had any bearing on individual susceptibility to the development of chronic obstructive pulmonary disease (COPD) and emphysema.

METHODS

We designed PCR-based genotyping assays to detect variant forms of mEPHX that confer slow and fast activity. We used these assays to screen 203 blood-donor controls and groups of patients with asthma (n = 57), lung cancer (n = 50), COPD (n = 68), and emphysema (n = 94), who were attending specialised clinics in Edinburgh, UK.

FINDINGS

The proportion of individuals with innate slow mEPHX activity (homozygotes) was significantly higher in both the COPD group and the emphysema group than in the control group (COPD 13 [19%] vs control 13 [6%]; emphysema 21 [22%] vs 13 [6%]). The odds ratios for homozygous slow activity versus all other phenotypes were 4.1 (95% CI 1.8-9.7) for COPD and 5.0 (2.3-10.9) for emphysema.

INTERPRETATION

Genetic polymorphisms in xenobiotic enzymes may have a role in individual susceptibility to oxidant-related lung disease. Epoxide derivatives of cigarette-smoke components may be the cause of some of the lung damage characteristics of these diseases.

Emphysema and cutis laxa

Images

Ehlers-Danlos syndrome with abnormal collagen fibrils, sinus of Valsalva aneurysms, myocardial infarction, panacinar emphysema and cerebral heterotopias

A 30 year old woman with marked joint hypermobility had severe, progressive lung disease, seizures, aneurysms of the sinuses of Valsalva and myocardial infarction documented during life. She died of intractable ventricular fibrillation, and postmortem examination showed myocardial injury in the distribution of the left coronary artery but no occlusive coronary artery disease. Severe panacinar emphysema was found in the lungs. Cerebral heterotopias with peculiar vascularization were present and were a likely cause of the seizure disorder. Electron microscopy showed dermal collagen fibrils to be heterogeneous in size, reduced in number, and irregular and frayed in appearance. This patient had a form of the Ehlers-Danlos syndrome, different from the 10 distinct variants described thus far, associated with lethal internal manifestations.