Desmosine as a biomarker of elastin degradation in COPD: current status and future directions

Desmosine (DES) and isodesmosine (IDES) are two unusual, tetrafunctional, pyridinium ring-containing amino acids involved in elastin cross-linking. Being amino acids unique to mature, cross-linked elastin, they are useful for discriminating peptides derived from elastin breakdown from precursor elastin peptides. According to these features, DES and IDES have been extensively discussed as potentially attractive indicators of elevated lung elastic fibre turnover and markers of the effectiveness of agents with the potential to reduce elastin breakdown. In the present manuscript, immunology-based and separation methods for the evaluation of DES and IDES are discussed, along with studies reporting increased levels of urine excretion in chronic obstructive pulmonary disease (COPD) patients with and without alpha(1)-antitrypsin deficiency. The results of the application of DES and IDES as surrogate end-points in early clinical trials in COPD are also reported. Finally, recent advances in detection techniques, including liquid chromatography tandem mass spectrometry and high-performance capillary electrophoresis with laser-induced fluorescence, are discussed. These techniques allow detection of DES and IDES at very low concentration in body fluids other than urine, such as plasma or sputum, and will help the understanding of whether DES and IDES are potentially useful in monitoring therapeutic intervention in COPD.

A review of the alpha-1 foundation: its formation, impact, and critical success factors

Patient-advocacy organizations have proliferated because they can be an effective method to advance research and clinical care for those with the index condition, and can produce substantial benefits for the affected community, especially when the condition is uncommon. To clarify critical success factors in organizing a patient-advocacy organization and to provide a blueprint for others, including the respiratory-care advocacy community, this report examines features of one highly successful organization, the Alpha-1 Foundation, which is committed to helping those with the genetic condition alpha-1 antitrypsin deficiency. Features of the Alpha-1 Foundation that underlie its success include: consistently creating partnerships with key stakeholders, including the scientific and clinical communities, government, and pharmaceutical manufacturers; bringing passion to the cause (eg, by assuring that organizational leadership is provided by individuals affected by alpha-1 antitrypsin deficiency); and developing strategic business partnerships, as with a company that administers alpha-1 antitrypsin treatment (so-called intravenous augmentation therapy) and employs individuals with alpha-1 antitrypsin deficiency. Funds allocated by the company help to underwrite the foundation's research-funding commitment. The foundation also recruits and retains talent, including alpha-1 patients, to leadership roles (eg, on the board of directors) and has a voluntary group of committed scientists and clinicians. We believe that attention to these factors can help assure the success of patient-advocacy groups.

Induction of the myofibroblast phenotype following elastolytic injury to mouse lung

The repair of alveolar structures following endotracheal administration of porcine pancreatic elastase (PPE) to mice involves the coordinated deposition of new matrix elements. We determined the induction of the myofibroblast phenotype following elastolytic injury to mouse lung by examining the expression of alpha-smooth muscle actin (alpha-SMA) by immunohistochemistry. We also examined elastin and alpha1(I) collagen mRNA expression by in situ hybridization. Changes in airspace dimensions were assessed by determining mean linear intercept. In untreated mice, alpha-SMA was localized to vascular structures and large airways, with no detectable expression in alveolar units. PPE induced alpha-SMA expression in damaged areas surrounding large vessels, in septal remnants, and in the opening ring of alveolar ducts. Elastin and alpha1(I) collagen mRNA expression were up-regulated in residual alveolar structures and septal walls. PPE dose-response studies indicated that alpha1(I) collagen and elastin mRNA expression were not induced in areas of normal lung adjacent to damaged lung. The administration of low dose PPE resulted in increased alpha-SMA protein and elastin mRNA expression in the cells comprising the opening ring of alveolar ducts. Our data suggest that repair mechanisms following elastolytic injury are confined to overtly damaged alveolar structures and involve the induction of the myofibroblast phenotype.

Veterans Administration support for medical research: opinions of the endangered species of physician‐scientists 1

Over the past three decades the Veterans Affairs (VA) Research program has evolved into a powerful, peer-reviewed funding mechanism for basic and translational research that has resulted in numerous important contributions to medical science and improvements in patient care. Continuity in VA Merit Review funding has fostered and nurtured the scientific careers of a large number of physician-scientists who have remained devoted to the mission of performing creative and innovative research that affects the patient care mission of the VA. VA medical research policies have undergone a major overhaul in the past year. Although many of these changes (de-emphasizing bench research and revamping the peer review process) have recently been reversed, the future direction of VA research remains in flux. The goal of this manuscript is to demonstrate the importance of the Merit Review medical research funding mechanism not just to the VA, but to the entire nation's health care system. To achieve this goal, the opinions of 65 established VA medical investigators were obtained regarding the past success and future direction of VA research. The conclusions reached include the following. 1) Merit Review research funding has been essential to the training, recruitment, and retention of productive VA physician-scientists. 2) The VA research program has contributed both basic and clinical innovations that have led to improvements in medical care. Contributions of VA researchers to excellence in many aspects of patient care at VA hospitals have been extraordinary. 3) Development of initiatives that entice outstanding Ph.D.'s to develop their careers in the VA has been crucial to the success of the program. 4) The VA research program has fostered a mutually beneficial relationship with affiliated medical schools. 5) Better methods to quantify VA research contributions and outcomes are essential for future program development.

Report of a workshop: quantitative computed tomography scanning in longitudinal studies of emphysema

It has been reported that quantitative computed tomography (CT) scanning of the lungs showed decreased progression of emphysema in a randomised clinical trial in patients with severe alpha1-antitrypsin (alpha1-AT) deficiency receiving monthly intravenous augmentation therapy with human alpha1-AT. Comparable results were not obtained using rate of decline of forced expiratory volume in one second. Accordingly, the Alpha-1 Foundation convened a workshop to explore the feasibility of using quantitative CT data as a primary outcome variable in trials of drugs for treating alpha1-AT deficiency. This report reviews the following: the principles for the use of modern CT scanners for quantifying emphysema; the methods and data on validation by comparison with measurements of severity of emphysema in inflation-fixed specimens of lungs; and the possibility of decreasing radiation dosage from CT to make it safe and ethically possible to use CT in longitudinal studies. The workshop concluded that it is feasible, safe and ethically possible to use computed tomography in longitudinal studies of emphysema. It recommended that the primary end-point should be a significant shift in the 15th percentile of lung density.

Scanning tunneling microscopy and spectroscopy investigations of QCA molecules

Quantum-dot cellular automata (QCA), a computation paradigm based on the Coulomb interactions between neighboring cells. The key idea is to represent binary information, not by the state of a current switch (transistor), but rather by the configuration of charge in a bistable cell. In its molecular realization, the QCA cell can be a single molecule. QCA is ideally suited for molecular implementation since it exploits the molecule's ability to contain charge, and does not rely on any current flow between the molecules. We have examined using an UHV-STM some of the QCA molecules like silicon phthalocyanines and Fe-Ru complexes on Au (111) and Si (111) surfaces, which are suitable candidates for the molecular QCA approach.

Retinoic acid does not affect alveolar septation in adult FVB mice with elastase-induced emphysema

BACKGROUND

Administration of ALL-TRANS retinoic acid (ATRA) to adult Sprague-Dawley rats with emphysema induced by porcine pancreatic elastase (PPE) reversed the emphysema perhaps by inducing new alveolar formation.

OBJECTIVE

A study was conducted to determine whether ATRA can induce new alveolar septa and reverse the airspace enlargement caused in adult mice by PPE treatment.

METHODS

48 FVB mice were divided into 6 groups. Three groups received 15 microg of PPE in 0.1 ml of 0.9% saline and 3 groups received 0.1 ml of saline, intratracheally. Starting at day 22, the mice received 12 daily intraperitoneal injections of cottonseed oil, with or without ATRA (12.5 microg or 50 microg). The mice were killed for study 1 day after the last injection.

RESULTS

Measurements of plasma and lung tissue ATRA levels showed statistically significant elevated levels after the 50-microg but not after the 12.5-microg doses of ATRA. In situ hybridization studies of elastin and alpha(1)(I) collagen mRNA expression in pulmonary parenchyma as well as in airways and blood vessels showed no effect of ATRA. Airspace size was determined by the mean linear intercept (Lm) method. The Lm of the groups receiving PPE and ATRA (46.2 +/- 4.1 microm, mean +/- SD) was not significantly different from the group receiving PPE and oil (47.8 +/- 6.0 microm). The Lm for groups receiving saline and ATRA (40.6 +/- 2.5 microm) were not significantly different from the group receiving saline and oil (41.0 +/- 2.7 microm). Comparison of the fixed lung volume data and calculated internal surface area also showed no differences between the control and ATRA-treated groups.

CONCLUSION

ATRA treatment does not affect airspace size or expression of elastin or alpha(1)(I) collagen mRNA in adult FVB mice with PPE-induced emphysema.

Enhancement of exercise performance in COPD patients by hyperoxia: a call for research

This essay summarizes 16 reports, published since 1956, that describe the effects of hyperoxia on exercise endurance in persons with COPD who have severe airflow obstruction (ie, FEV(1) < 1.0 L or < 39% of predicted) and mild hypoxemia at rest (ie, PaO(2) > 62 mm Hg or arterial oxygen saturation [SaO(2)] measured by pulse oximetry of > 91%). The term hyperoxia is used because, in a proportion of study participants, oxygen administration increased exercise endurance in a dose-dependent fashion, up to a fraction of inspired oxygen of 0.5 or a flow of 100% O(2) of 6 L/min. The process appears to be dependent on an increase in PaO(2) rather than on the restoration of SaO(2) to normal levels. The results of pulmonary function tests were not predictive of response. Increased exercise performance was associated with a decrease in dyspnea, respiratory frequency, and minute ventilation. The slowing of respiratory frequency and the decrease in pulmonary air trapping likely accounted for the decrease in dyspnea. Slowing of the respiratory rate, which occurred at the expense of the retention of CO(2), is most likely due to a hyperoxia-induced decrease in chemoreceptor ventilatory drive from the aortic and carotid bodies. Research is called for to determine the following: (1) the prevalence of COPD patients who have severe airflow limitation accompanied by mild hypoxemia; (2) the proportion of these patients who show improvements in exercise performance during a test of hyperoxic exercise; and (3) whether enhanced exercise performance during a brief test translates into a meaningful increase in the ability to perform the activities of daily living.

Urinary desmosine excretion in acute exacerbations of COPD: a preliminary report

Desmosine (DES) is an elastin-derived, cross-link amino acid, which is not metabolized; hence, its urinary levels reflect elastin breakdown. We hypothesized that elastin degradation should increase as a result of increased lung inflammation during an acute exacerbation of COPD and should decrease after recovery. To test this hypothesis we measured DES in three urine samples from nine COPD subjects during the first 5 days of an acute exacerbation and at 2 months after recovery. We also measured forced expiratory volume in 1 sec (FEV1) to monitor the effects ofthe exacerbation on ventilatory function. The mean (SD) FEV1 was 45 (15)% predicted during the exacerbation and 57.8 (16)% predicted 2 months later (P=0.00001). The mean (SD) DES excretion was 25.3 (9) microg g(-1) creatinine at day 1;23.5 (9) at day 3 and 24 (9) at day 5 of the exacerbation. The mean (SD) urinary DES excretion 60 days after discharge was 20.9 (7) microg g(-1) creatinine (P=0.049) in comparison with the mean of the three acute-phase values. The size of the increase in desmosine excretion during exacerbation is small, 3.2 microg g(-1) creatinine or 16% of the recovery desmosine value. We conclude that there is a small but statistically significant increase in lung elastin breakdown in the body during an acute exacerbation of COPD.

Severity of elastase-induced emphysema is decreased in tumor necrosis factor-alpha and interleukin-1beta receptor-deficient mice

A single intratracheal dose of porcine pancreatic elastase, which is cleared from the lung by 24 hours, was administered to wild-type, IL-1beta type 1 receptor-deficient, double TNF-alpha (type 1 and type 2) receptor-deficient, and combined TNF-alpha (type 1 receptor) plus IL-1beta receptor-deficient mice. The mean linear intercept (Lm) of saline-treated mice was 32(3) microm [mean(SE)]. For wild-type elastase-treated mice, Lm was 81(6) microm at 21 days versus 52(5) microm at 5 days after treatment, indicating that alveolar wall remodeling occurs long after the elastase injury. At 21 days, Lm values were 67(10), 62(3), and 39(5) microm in elastase-treated mice deficient in the IL-1beta receptor, double TNF-alpha receptors, and combined receptors, respectively. The level of apoptosis assessed by a terminal deoxynucleotidyl transferase-catalyzed in situ nick end-labeling assay was increased at 5 days after elastase treatment and was markedly and similarly attenuated in the IL-1beta, the double TNF-alpha, and the combined receptor-deficient mice. Our results indicate that inflammatory mediators exacerbate elastase-induced emphysema. We estimate that in the combined TNF-alpha + IL-1beta receptor-deficient mice, inflammation accounts for about 80% of the emphysema that develops after elastase treatment; decreased apoptosis of lung cells likely contributes to decreased severity of emphysema.

Limitations of randomized clinical trials for evaluating emerging operations: the case of lung volume reduction surgery

Although unanswered questions remain, scores of observational studies and several small randomized clinical trials (RCTs) indicate that lung volume reduction surgery (LVRS) offers safe and effective palliation for a relatively well defined subset of patients with advanced emphysema. Nonetheless, Medicare and other insurers stopped reimbursement for the procedure. Subsequently, two multicenter RCTs on LVRS, the National Emphysema Treatment Trial (NETT) and the Overholt-BlueCross Emphysema Surgery Trial (OBEST), were launched with the stipulation that the procedure would not be paid for outside these trials. Thus access to LVRS has been denied to patients who could benefit but do not wish to participate in an RCT. Emerging operations, unlike new drugs or devices, pass through evolutionary changes and frequently fail to produce data that meet the scientific rigor required by randomized studies. In such a setting, the observational approach is more appropriate. Indeed, almost all operations in the present surgical armamentarium have been evaluated and have evolved through observational studies without the use of RCTs. By the time new operations are standardized and qualify for RCTs, benefits for certain patients may be demonstrated and randomization could involve unacceptable health hazards. Patients from this population should be offered the choice between participating in RCTs and having the operation outside the study. Imposition of financial restrictions that bars access to a therapy with known benefit is a questionable practice.

XAFS and X-ray reflectivity study of III-V compound native oxide/GaAs interfaces

Fluorescence-mode XAFS has been used to study the local environment about chosen atomic species such as Ga and As in bulk oxide Al(1-x)Ga(x)As (x=0.96) and at the interface between thin (300 A) oxidized Al(1-x)Ga(x)As (x=0.94) film and GaAs substrate in total external-reflection mode. X-ray reflectivity experiments have also been employed to investigate the density profile of the oxide film on a GaAs substrate revealing the density profile as a function of depth. It is important to find out how the As is incorporated at the interface, the interfacial strain, and related local structural parameters for understanding that may be central in developing high performance III-V MOSFET devices.

Short-term supplementation therapy does not affect elastin degradation in severe alpha(1)-antitrypsin deficiency. The American-Italian AATD Study Group

We evaluated the ability of intravenous supplementation therapy with alpha(1)-antitrypsin (AAT) to reduce the rate of urinary excretion of desmosine (DES), a specific marker of elastin degradation, in eight men and four women with emphysema due to severe, congenital deficiency of AAT (range 17-69 mg/dl). Nine were former cigarette smokers, two were current smokers, and one reported never smoking; their mean age was 54 (SD 12) yr and their mean FEV(1) was 41 (18%) of predicted. Urinary DES was measured by isotope dilution and HPLC. Prior to the start of AAT supplementation, mean DES excretion was 13.0 (5.0) microg/g creatinine, 73% higher than in healthy nonsmokers. During 8 wk of supplementation therapy, mean urinary DES excretion was 13.0 (5.9) microg/g creatinine, unchanged from the baseline period (p = 0.85 by repeated measures ANOVA). We conclude that baseline levels of elastin degradation in emphysematous patients with severe AAT deficiency were abnormally high and that 8 wk of AAT supplementation therapy did not appreciably reduce the rate of elastin degradation. These findings raise the possibilities that protective levels of AAT in the lungs are insufficient or that elastin degradation in the lungs of these subjects is not dependent upon neutrophil elastase at this time.

Partially suppressed shot noise in hopping conduction: observation in SiGe quantum wells

We have observed shot noise in the hopping conduction of two-dimensional carriers confined in a p-type SiGe quantum well at a temperature of 4 K. Moreover, shot noise is suppressed relative to its "classical" value 2eI by an amount that depends on the length of the sample and the carrier density. We have found a suppression factor to the classical value of about one-half for a 2 &mgr;m long sample, and of one-fifth for a 5 &mgr;m sample. In each case, the factor decreased slightly as the density increased toward the insulator-metal transition. We explain these results in terms of the characteristic length ( approximately 1 &mgr;m in our case) of the inherent inhomogeneity of hopping transport, obtained from percolation theory.

Digital logic gate using quantum-Dot cellular automata

A functioning logic gate based on quantum-dot cellular automata is presented, where digital data are encoded in the positions of only two electrons. The logic gate consists of a cell, composed of four dots connected in a ring by tunnel junctions, and two single-dot electrometers. The device is operated by applying inputs to the gates of the cell. The logic AND and OR operations are verified using the electrometer outputs. Theoretical simulations of the logic gate output characteristics are in excellent agreement with experiment.

Remodeling of alveolar walls after elastase treatment of hamsters. Results of elastin and collagen mRNA in situ hybridization

Treatment of hamster lungs with porcine pancreatic elastase (PPE) causes emphysema and a decrease in lung elastin content, which returns to control level by Day 30. To explore the mechanism of alveolar wall remodeling after elastolytic injury, we examined the expression of elastin and alpha1(I) collagen mRNAs by in situ hybridization at 1, 2, 3, 5, 7, and 30 d after intratracheal PPE. The lungs of control animals displayed weak signals for elastin and alpha1(I) collagen mRNA in pleura, large arteries, veins, and airways. There was little or no signal in respiratory air space walls. Increased expression of elastin and alpha1(I) collagen mRNA began by Day 1 after PPE and reached an asymptote by Day 3 that was maintained by elastin until Day 7; expression of alpha1(I) collagen mRNA waned earlier. Elastin and, to a lesser extent, alpha1(I) collagen mRNA were heavily expressed in pleura, blood vessels, and airways. Analysis of serial sections showed elastin message was minimal in the walls of respiratory air spaces and when present, at 3, 5, and 7 d, was primarily found at the free margins of alveolar septa. Collagen message was very sparse in respiratory air space walls. By 30 d, elastin mRNA expression was reduced but still above control levels and emphysema was widespread and severe. Rank score of elastin mRNA expression in individual subpleural air spaces showed a positive correlation with air space size. In conclusion, most expression of elastin and alpha1(I) collagen mRNA occurs in the pleura, airway, and vascular walls. In respiratory air space walls, expression of elastin mRNAs occurs in damaged tissue at free septal margins.

Distribution of elastin in hamsters and the turnover rates of different elastin pools

Desmosine (DES) and isodesmosine (IDES) concentration in the urine can be used as a noninvasive method of assessing degradation of mature elastin in normal and pathologic states. The present study was undertaken to determine the distribution of elastin among organs and tissues of normal hamsters, and to determine the turnover rates of two elastin-containing organs (lung, thoracic aorta) as a reflection of their contributions to DES and IDES excretion in the urine. Hamsters were metabolically labeled at 5 days of age with 14C-lysine and studied at 1.5, 4.5, 8, and 12 months of age. The aorta DES + IDES-associated radioactivity did not change significantly over the age span of 1.5-12 months. Lung DES + IDES-associated radioactivity decreased with a half-life of 420 days. Measurement of DES + IDES pools in other tissues, with relatively low concentrations of elastin, was carried out by the isotope dilution technique. At 12 months of age, the head and paws pool, skin, skeletal muscle, gastrointestinal tract, heart-liver-kidney-spleen pool, lungs, and thoracic aorta represented 37%, 28%, 13%, 11%, 6%, 4%, and 1%, respectively, of total body DES + IDES. The organs with the highest DES + IDES-specific radioactivity at 12 months were heart-liver-kidney-spleen, lung, and gastrointestinal tract, with 310, 217, and 217 dpm/nmol, respectively. Skin had the lowest specific radioactivity, with 90 dpm/nmol. The specific radioactivity of DES + IDES in urine was 62 dpm/nmol at 12 months, down from 251 dpm/nmol at 1.5 months. These data clearly indicate that non-lung tissues contain a high proportion of the total body DES + IDES and suggest that pathology in these other pools of DES + IDES could result in significant elevation of urinary DES + IDES. Nevertheless, the relatively high specific radioactivity of DES + IDES in lung elastin as compared with urine makes monitoring labeled urinary DES + IDES in this animal model a sensitive tool for assessing elastin degradation in experimental lung disease.

Tuberculosis then and now: a personal perspective on the last 50 years

Rates of death from tuberculosis in the United States decreased from 194 per 100,000 persons in 1900 to 40 per 100,000 persons in 1945, in part because the epidemic of tuberculosis in the western world was running its course and in part because of public health initiatives and improved socioeconomic conditions. In 1945, 63,000 persons died of tuberculosis and 115,000 new cases of the disease emerged. Streptomycin and para-aminosalicylic acid had just been discovered; the discovery of isoniazid followed, in 1952. Sanitarium care, nonsurgical and surgical collapse therapy, and resectional surgery were in widespread use. By the middle of the 1950s, it was evident that bedrest did not add to the benefit produced by effective chemotherapy, and sanitariums began to close, a process that was completed by the 1970s. As mortality and morbidity due to tuberculosis rapidly decreased, the U.S. government decreased funding for tuberculosis and many states and cities downgraded their tuberculosis control programs. After 1984, the rate of new cases of tuberculosis, which had decreased to 9.4 per 100,000, began to increase and focal outbreaks of multidrug-resistant tuberculosis were reported. Noncompliance with drug therapy, homelessness, immigration to the United States from developing countries, and human immunodeficiency virus (HIV) infection were invoked as explanations. With the reinstitution of federal funding, improved case-finding and surveillance, and the practice of having patients receive therapy while under direct observation, the rate of new cases of tuberculosis decreased to 8.7 per 100,000 in 1995, the lowest rate since national surveillance was begun in 1953. However, at the end of the 20th century, the worldwide burden of tuberculosis, which is engrafted onto the pandemic of HIV infection, is enormous: an estimated 7.6 million new cases in developing countries and 400,000 new cases in industrial nations.

Urinary desmosine excretion in smokers with and without rapid decline of lung function: the Normative Aging Study

It is hypothesized that smoking-related chronic obstructive pulmonary disease (COPD) results in part from excess lung elastin degradation. Taking advantage of spirometry performed over a 12-yr period at the Normative Aging Study, we conducted a nested case-control study of elastin and collagen degradation rates in current smokers with (n = 10) and without (n = 8) rapid decline of lung function, using a biochemical assay for urinary desmosine (DES), a specific marker for mature elastin degradation, and hydroxylysylpyridinoline (HP), a specific marker for mature fibrillar collagen degradation. Mean urinary excretion of DES in rapid decliners was 36% greater than in slow decliners (9.8 +/- 0.7 [mean +/- SE] versus 7.2 +/- 0.4 microg/g creatinine, p < 0.01); after adjustment for age and lean body mass (LBM), DES excretion in rapid decliners was 30% greater than in slow decliners (9.6 +/- 0.6 versus 7.4 +/- 0.7 microg/g creatinine, p = 0.06). Among rapid decliners, there was no difference in DES excretion between those with and those without computed tomogaphic evidence of emphysema. There was no significant difference between rapid and slow decliners in mean urinary excretion of HP (24.7 +/- 1.4 versus 21.6 +/- 1.8 nmol/mmol creatinine, p = 0.18). Among all subjects, rate of decline of FEV1 was significantly correlated with DES excretion (r = 0.61, p < 0.01). In a linear regression model adjusting for age and LBM, an increase in DES excretion of 1 microg/g creatinine was associated with an excess decline of FEV1 of 10.6 ml/yr (p = 0.04). This study provides further evidence in support of the elastase-antielastase hypothesis of the pathogenesis of COPD, and it suggests a role for elastin degradation in both emphysema and small airways disease. Moreover, it suggests that urinary DES excretion may be a useful biochemical marker for the study of interventions designed to prevent the development or progression of COPD.

Health-care technology assessment of surgical procedures: the case of reduction pneumoplasty for emphysema

End-stage chronic obstructive pulmonary disease (COPD) is frequent in the practice of pulmonology. The recent report that reduction pneumoplasty results in lung function improvement in a high proportion of patients with emphysema has raised the question of how effectively the medical profession assesses the efficacy of new surgical procedures. Unlike drugs and devices, the introduction of new surgical procedures is not regulated. Technique changes rapidly for a period of time after new procedures are introduced. Peer review is done mainly by quality-improvement activities in the surgeon's hospital and by publication in peer-reviewed journals. Randomized clinical trials (RCT) are procedurally and ethically difficult to do and few have been done for new surgical procedures. Some trials have been problematic. For example, a controlled cooperative trial of radial keratotomy resulted in unsuccessful antitrust suits brought by physicians and patients alleging that third-party payers would not reimburse them for surgery. RCTs that have been done have tended to be reported long after the procedure has been incorporated into surgical practice. A RCT of reduction pneumoplasty would be impossible at this time because of rapid flux in surgical techniques. There might also be ethical problems because of the substantial improvement in lung function of many patients in the existing case series, a level of improvement seen with no other treatment than lung transplantation. It is proposed that a prospective, cooperative, consecutive-case, observational study (registry) of reduction pneumoplasty for emphysema could greatly speed the acquisition of information about the efficacy of this new procedure.

Reduction pneumoplasty for giant bullous emphysema. Implications for surgical treatment of nonbullous emphysema

A review of the literature on reduction pneumoplasty for giant bullous emphysema was undertaken to identify current criteria for this surgical treatment and in the hope of obtaining insights into evaluating reduction pneumoplasty for nonbullous emphysema. Twenty-two retrospective case series, published since 1950, were retrieved by a computer search of the literature and a search of the Index Medicus prior to 1966. Reduction pneumoplasty is most effective when bullae are larger than one third of a hemithorax with evidence of compression of adjacent lung tissue and an FEV1 of less than 50% predicted; the presence of emphysema in nonbullous lung and the amount of compression are best judged by CT. The rationale for reduction pneumoplasty for nonbullous emphysema is supported by the similar early functional changes after reduction pneumoplasty for bullous and nonbullous-improvement of blood gas values and lung mechanics. A single study showing that decline of lung function after surgery for bullous emphysema was less in those who stopped smoking than in those who continued to smoke supports the need for preoperative and maintained smoking cessation in patients receiving reduction pneumoplasty. After 4 decades, the duration of improvement in lung function, whether worsening of emphysema occurs in remaining lung, and late morbidity and mortality after reduction pneumoplasty for bullous emphysema are not well defined. A registry with an unoperated-on comparison group could more rapidly accumulate such data after reduction pneumoplasty for nonbullous emphysema.

Differential expression of elastin and alpha 1(I) collagen mRNA in mice with bleomycin-induced pulmonary fibrosis

Interstitial pulmonary fibrosis is characterized by increased production of connective tissue components, including collagen and elastin. The role of elastin turnover in pulmonary fibrosis is not clear, and it is not known whether elastin and collagen are regulated separately or together during the inflammatory process. Mice with bleomycin-induced pulmonary fibrosis were investigated to determine the temporal and spatial changes in localization of elastin mRNA expression, as well as to compare elastin mRNA expression with that of alpha 1(I) collagen mRNA expression. In control (saline-treated) lungs, elastin mRNA was detected by in situ hybridization in arterial walls. No signal was found in alveolar or airway walls or in pleura; alpha 1(I) collagen mRNA was detected in the tissue underlying the airway epithelium. An increase in elastin mRNA expression in muscular arteries was observed 3 days after bleomycin instillation. Expression was also seen in the adventitia of terminal airways and adjacent small blood vessels. Expression of alpha 1(I) collagen mRNA increased in the tissue underlying the airway epithelium. In the pleura, alpha 1(I) collagen mRNA expression was found, although no pleural thickening was evident. The alpha 1(I) collagen mRNA expression was particularly increased in the adventitia of terminal airways and in associated small blood vessels. Obvious in areas of fibrosis, elastin mRNA expression was occasionally increased in the pleura and airway wall 7 days after bleomycin treatment; alpha 1(I) collagen mRNA expression was generally stronger than elastin mRNA expression in areas of fibrosis and was frequently intense in the adventitia of airways and associated blood vessels. The fibrotic areas showed increased elastin mRNA expression 14 and 30 days after bleomycin treatment. The arteries in fibrotic areas showed normal elastin mRNA levels. In the areas of fibrosis and in the adventitia of airways and adjacent blood vessels, alpha 1(I) collagen mRNA expression was very high. In conclusion, lung elastin biosynthesis is markedly altered by bleomycin treatment. The localization and intensity of elastin mRNA expression is different from the expression of alpha 1(I) collagen mRNA.

Elastin and collagen degradation products in urine of patients with cystic fibrosis

Elastin degradation has been reported to be increased in patients with cystic fibrosis (CF). In order to further explore evidence for elastin degradation in a group of 18 patients with CF with a wide range of disease severity, we used an isotope dilution method to measure urinary desmosine (DES) and isodesmosine (IDES), amino acids derived exclusively from cross-linked elastin, and hydroxylysylpyridinoline (HP) and lysylpyridinoline (LP), amino acids derived exclusively from cross-linked collagen. Urinary DES and IDES (mean +/- SD) were 23.9 +/- 30.7 and 18.5 +/- 22.4 micrograms/g creatinine, respectively, in the patients with CF versus 7.5 +/- 1.7 and 6.8 +/- 1.4 micrograms/g creatinine, respectively, in 10 healthy control subjects (p < 0.001); only two patients with CF had DES values within the control range. The values of urinary HP and LP in the CF group were 54.9 +/- 39.1 and 12.3 +/- 8.6 nmol/mmol creatinine, respectively, versus 24.5 +/- 5.8 and 5.1 +/- 2.7 nmol/mmol creatinine, respectively, in the controls (p < 0.005). Both HP and LP were highly correlated (r = 0.71, p < 0.0001). Patients with CF had active pulmonary inflammation; neutrophils were abundant in the bronchoalveolar lavage fluid of the CF group and correlated with elastase activity measured with methoxysuccinyl Ala-Ala-Pro-Val paranitroanilide (r = 0.61, p < 0.05). Airway neutrophils had decreased expression of the complement receptor CR1 (CR1/CR3 of 0.17 +/- 0.15 versus 1.0 for blood neutrophils), a change known to be caused by uninhibited neutrophil elastase. We conclude that lung elastin is the most likely source of the increased DES and IDES in CF.

Cross-linked elastin and collagen degradation products in the urine of patients with scleroderma

OBJECTIVE

To measure the urinary excretion of specific cross-link amino acid markers for mature elastin (desmosine [DES] and isodesmosine [IDES]) and fibrillar collagen (hydroxylysylpyridinoline [HP] and lysylpyridinoline [LP]) in systemic sclerosis (SSc) patients and healthy controls.

METHODS

Urine specimens from 20 patients with SSc and 22 controls were assessed for DES, IDES, HP, and LP using high performance liquid chromatography and ultraviolet absorption spectroscopy, in combination with an isotope dilution technique in which the urine specimen was spiked with isotopically labeled cross-link amino acids.

RESULTS

Mean +/- SD levels of urinary DES and IDES were elevated in SSc patients by 2-3-fold, and urinary HP and LP by 3-4-fold, compared with controls (DES 21.0 +/- 9.4 versus 7.5 +/- 1.4 micrograms/gm creatinine; HP 109.0 +/- 72.9 versus 24.9 +/- 5.7 nmoles/mmole creatinine). Nineteen of the 20 SSc patients had urinary DES and HP values that were > 3 SD above the control mean. A significant elevation in the HP:LP ratio in SSc patients as compared with controls (mean +/- SD 6.9 +/- 1.5 versus 5.5 +/- 1.3) indicated a soft tissue origin for much of the increased HP.

CONCLUSION

Patients with SSc have higher levels of urinary cross-link amino acids specific for the degradation of mature collagen and elastin. These markers distinguish most SSc patients from healthy controls.

Elastin and collagen degradation products in urine of smokers with and without chronic obstructive pulmonary disease

It has been hypothesized that emphysema results from damage to the elastic fiber network of the lungs as a result of elastase-antielastase imbalance. We used a new assay for urinary desmosine (DES) and isodesmosine (IDES), specific markers for the degradation of mature crosslinked elastin, and hydroxylysylpyridinoline (HP) and lysylpyridinoline (LP), specific markers for the degradation of mature crosslinked collagen, in order to examine elastin and collagen degradation in relation to current cigarette smoking and the presence of chronic obstructive pulmonary disease (COPD). The study sample consisted of 22 never-smokers (NSM group), 13 current smokers without airflow obstruction (SM group), and 21 patients with COPD (COPD group), including both current and former smokers. The relation between the creatinine-height index and FEV1 was used to correct for possible loss of muscle mass and decreased excretion of creatinine in the COPD group. Mean urinary excretion of elastin-derived crosslinks in the COPD group (DES, 11.8 +/- 5.1 [mean +/- SD]; IDES, 11.3 +/- 5.0 micrograms/g creatinine) and in the SM group (DES, 11.0 +/- 4.2; IDES, 10.2 +/- 2.5 micrograms/g creatinine) was significantly higher than in the NSM group (DES, 7.5 +/- 1.4; IDES, 6.9 +/- 1.3 micrograms/g creatinine). In multivariate analysis, current smoking and the presence of COPD were significantly and independently associated with higher urinary excretion of elastin degradation products, and there was no significant interaction between current smoking and the presence of COPD.(ABSTRACT TRUNCATED AT 250 WORDS)

Preliminary evidence that augmentation therapy diminishes degradation of cross-linked elastin in alpha-1-antitrypsin-deficient humans

It is hypothesized that emphysema develops in some severely alpha 1-antitrypsin (AAT)-deficient persons because endogenous elastases are not adequately controlled by AAT, and accelerated elastin degradation occurs. It is not known whether augmentation therapy with AAT diminishes degradation of lung elastin in severely deficient persons with lung disease. Two severely deficient, PiZ patients were studied, a 63-year-old never-smoking woman with bronchiectasis and a 41-year-old smoking man with emphysema. Urinary desmosine (DES) was determined before and after augmentation therapy with AAT, 260 mg/kg/month. Mean +/- SEM pretreatment urinary DES was elevated in both patients, 19.7 +/- 0.9 (n = 2) and 10.8 +/- 0.2 (n = 2) micrograms/g creatinine, respectively, compared to normal values of 7.5 +/- 0.3 (n = 22) micrograms/g creatinine. Following augmentation therapy, urinary DES values decreased 40 and 36%, respectively, to 11.9 +/- 0.3 (n = 8) and 6.9 +/- 0.4 (n = 7) microgram/g creatinine (p < 0.05). We conclude that monthly AAT augmentation therapy decreased DES excretion in the urine of these PiZ patients. We speculate that since there was lung disease in both patients, a decrease in degradation of lung elastin is the most likely explanation for this observation.

Pitfalls in antiprotease therapy of emphysema

Many individuals with emphysema are unable to stop smoking despite the best efforts of specialists in smoking cessation. Because emphysema is a slowly progressive disease, it is rational to attempt to develop drugs for it. The hope is that drug therapy will slow the rate of decline of lung function, thereby delaying the onset of disability and prolonging life. The major emphasis in drug development has been on antiproteases having the ability to inhibit neutrophil elastase. There are a number of potential pitfalls in the development of such drugs. Although there is gathering evidence that elastin degradation is a part of the development of human emphysema, it is evident from studies in experimental emphysema that protease-antiprotease imbalance is not the only pathogenetic mechanism that gives rise to emphysema. There is strong evidence that human centrilobular and panacinar emphysema are different in pathogenesis. Indeed, airspace enlargement may be considered one of the stereotyped ways that the lung heals after a variety of injuries. There is accumulating evidence that macrophages as well as neutrophils may participate in elastolysis; antiproteases designed to inhibit neutrophil elastase may not inhibit the metalloproteases produced by macrophages. Some antiproteases may serve to transport elastase into the interstitium of the lung and actually increase the risk of emphysema. A process study of antiprotease therapy, using a measure of alteration of elastase burden of the lungs and urinary elastin peptides and desmosine measurements as markers of elastin degradation is now feasible. An outcome study of antiprotease therapy of emphysema should not be undertaken unless there is evidence from a process study that an antiprotease has biochemical efficacy and no unacceptable side effects.

Effect of diet on urinary excretion of desmosine and hydroxylysyl pyridinoline

To help validate the use of urinary desmosine (DES), isodesmosine (IDES), and hydroxylysyl pyridinoline (HP) as specific markers of host elastin and collagen degradation, respectively, a study was carried out on the effect of dietary elastin and collagen on urinary DES, IDES, and HP. Ingestion of a meal of calf ligamentum nuchae containing 33 g elastin, 500 mg DES, and 400 mg IDES produced a 10-fold increase in urinary DES and an 8-fold increase in IDES. The urinary DES values remained elevated for more than 10 days following the ingestion. We estimate that about 0.3 mg, or < 0.1%, of the ingested DES was excreted in the urine. Since ligamentum nuchae is not a usual ingredient of human diets, we also determined whether a more typical source and amount of DES, IDES, and HP might affect urinary DES, IDES, or HP values. Lean ground beef (454 g) was ingested. Our analysis showed that this meal contained 4 mg DES, 2 mg IDES, and 0.9 mg HP. The meat-rich diet caused a significant increase of 16 and 34% in the creatinine and DES content of the urine, respectively. When DES, IDES, and HP values were normalized for the urine creatinine content, diet had no effect on the measured amounts. The baseline values (mean +/- SE) for the volunteers before ingestion of the beef were 8.3 +/- 0.7 micrograms DES/24 h, 8.3 +/- 0.6 micrograms IDES/24 h, and 340 +/- 48 nmol HP/24 h; 5.7 +/- 0.5 micrograms DES/g creatinine, 5.6 +/- 0.4 micrograms IDES/g creatinine, and 26.9 +/- 2.2 nmol HP/mmol creatinine.(ABSTRACT TRUNCATED AT 250 WORDS)